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Dermatology Dictionary

A

Acne Vulgaris

Acne is chronic inflammation of the pilosebaceous units (hair follicle and oil gland) of the face and trunk that commonly begins during adolescence. Acne presents clinically with comedones, papules, nodules, cysts or papulopustules, sometimes followed by pitted or hypertrophic scars. An overproduction of oil, an overgrowth of P. acne bateria and a clogging of the pores are the main cause acne. This condition can be aggravated by stress, illness or comedogenic cosmetics. It is unclear as to whether diet plays a direct role in acne.

Aging Skin

As the body ages, the appearance and characteristics of the skin alter. Aging is accelerated in skin exposed to sunlight (ultraviolet radiation), a process known as 'photoaging.' This is particularly apparent on the face, and occurs at an early age in fair skinned people who have spent much time outdoors. The result of photoaging is lines and wrinkles, brown freckles called lentigos, yellowing of the skin, dilated capillaries (telangiectases), blackheads and whiteheads (senile comedones) and a dry complexion. Aging skin should be regularly examined for precancerous and cancerous lesions. Photodamaged skin can be treated laser therapy.

Allergic Contact Dermatitis

Allergic contact dermatitis is an itchy skin condition caused by an hypersensitivity reaction to material in contact with the skin. This type of reaction occurs after the immune system processes the absorbed material and mounts an immune response against it. This reaction causes severe itching, swelling and redness in the affected area. Poison ivy is a classic example of this condition.

Alopecia Areta

Alopecia areata consists of round patches of hair loss that appear suddenly. Any hair-bearing area can be affected but the scalp is most common. Alopecia areata is caused by an immune reaction targeting individual hair follicles. Regrowth can occur spontaneously and is often treated with topical or intralesional medications. It can occur at any age, is not contagious, and sometimes starts after a stressful event. Alopecia areata has three stages: First there is sudden loss of hair; then enlargement of the patches of hair loss; Lastly new hair usually grows back. This may take many months to resolve.

Androgenetic Alopecia

Male pattern hair loss is characterized by a receding hairline and/or hair loss on the top of the head. Male pattern hair loss is an inherited condition, caused by a genetically determined sensitivity to the effects of dihydrotestosterone, or DHT. DHT is believed to shorten the growth, or anagen, phase of the hair cycle, causing miniaturization of the follicles, and producing progressively finer hairs. An enzyme called 5-alpha reductase regulates the production of DHT.

APEC

Asymmetric Periflexural Exanthema of Childhood (APEC) is an uncommon rash affecting young children. It is suspected to be due to a viral infection, mainly occurs in winter and spring and affects twice as many girls as boys. The average age is two, most cases being between one and five years old. The rash is often mistaken for eczema (dermatitis) or a fungal infection (ringworm). It usually starts in the armpit or groin and gradually extends outwards, remaining predominantly on one side of the body. It may spread to the face, genitalia, hands or feet. The rash begins as a tiny-raised pink spots, which may be surrounded by a pale halo, then slowly becomes flat and scaly. The middle of older patches fades to a dusky gray. Occasionally the patches are net-like or in rings. Little blisters or blood spots may occur. The rash is usually quite itchy.

Atopic Dermatitis

Atopic dermatitis (also called eczema) is the name given to a stubborn itchy rash, which occurs in certain people with sensitive skin. Atopic dermatitis is common in infants and small children (affecting about one in seven), but it usually clears before adulthood. Eczema may clear for years, only to reappear later at a different site. The exact cause is unknown. It is probably the result of an inborn defect of the skin that tends to run in families; other family members often have asthma or hay fever. Atopic eczema is not contagious and does not affect one's general health. The skin is usually dry and easily irritated by soap, detergents and woolen clothing. Eczema may be aggravated by hot weather and a wide variety of environmental factors both at home and at work. These include dust, cats, emotional stress, and rarely foods.

B

Basal Cell Carcinoma

Basal cell carcinoma is the most common type of cancer in humans. Yet, it is very rarely a threat to life. Basal cell carcinoma typically affects people of fair complexion who have had a lot of sun exposure, or repeated episodes of sunburn. The tendency to develop Basal cell carcinoma may be inherited. Basal Cell Carcinoma can vary in size from a few millimeters to several centimeters in diameter. They usually grow slowly over months or years.

Blue Nevus

A blue nevus is a rather unusual appearing mole. It may be found anywhere on the body. A blue nevus usually appears on older children and teenagers, but may develop at any age. It is a dark blue color because the color or pigment is deeper in the skin than it is with the commoner brown moles and freckles.

Boils (see also furunculosis)

Boils are caused by an infection of the hair follicles with the bacteria Staphylococcus aureus. Most people with boils are otherwise healthy and have good personal hygiene. They do however carry Staphylococcus aureus on the surface of their skins (Staphylococcus carrier state). Why this occurs is usually not known, but it is estimated that 10 - 20% of the population are Staphylococcus carriers.

Botox Treatments

A naturally produced chemical injected into selective muscles temporarily eliminates facial expression lines such as frown lines, crows feet around the eyes, forehead lines and lip lines.

Bullous Pemphigoid

Bullous pemphigoid is a blistering skin disease, which usually affects middle aged or elderly persons. Characteristically, crops of tense, fluid -filled blisters develop. They may arise from normal-looking or reddened skin, often in body folds. Usually, the skin is very itchy. Although sometimes pemphigoid is localized to one area such as an ankle, it is usually widespread. The diagnosis is confirmed by taking a skin biopsy of a typical blister. Under the microscope, the pathologist can see a split between the main layers of the skin, the epidermis and the dermis. This occurs because antibodies and white blood cells attack the membrane that holds the skin together.

C

Candida

Candida is the name for a group of yeasts (a type of fungus) that commonly infect the skin. The name "candida" refers to the white color of the organisms in culture. Candidal infection is known as "candidiasis", "candidosis" or "moniliasis". Candida depends on a living host for survival. It is a normal inhabitant of the human digestive tract from early infancy, where it lives without causing any disease most of the time. However, if the host's defences are lowered, the organism can cause infection of the mucosa (the lining of the mouth, anus and genitals), the skin, and rarely, deep-seated infection.

Capillaritis

Capillaritis is the name given to a harmless skin condition in which there are reddish -brown patches caused by leaky capillaries. It is also known as pigmented purpura. The capillaries are small blood vessels near to the skin surface. For unknown reasons they sometimes become inflamed. Blood cells may pass through small gaps that arise between the cells, which make up the capillary walls. The result is tiny red dots appear on the skin, described as cayenne pepper spots. They group together to form a flat red patch, which becomes brown and then slowly fades away over weeks to months.

Cat Scratch Disease

CSD is a benign self-limited zoonotic infection, characterized by a primary skin or eye lesion, following cat scratches or contact with a cat and subsequent tender lymph nodes. The inoculation site resemble a pimple which may ulcerate. Occasionally there may be high fevers and severe systematic symptoms.

Cellulitis

Cellulitis is a sudden spreading infection of dermal and subcutaneous tissues (tissues underneath the skin) characterized by a red hot tender area of skin, often at the site of bacterial entry, caused most frequently by group A beta-hemolytic streptococci or staphylococcus aureus. Patients often have associated malaise, anorexia, fever, and chills. If untreated cellulitis can be life threatening.

Chickenpox

Chickenpox is also known as Varicella. Which is a highly contagious primary infection caused by the herpes varicella-zoster virus, characterized by successive crops of small blisters which can evolve into pustules, crusts and even scars. There is often associated headache, fever, generalized aches, and malaise. In adults the disease is usually more severe and may lead to pneumonia, encephalitis and myocarditis.

Chilblains

Chilblains are itchy and/or tender red or purple bumps that occur as a reaction to cold. They are also known as pernio. Chilblains occur several hours after exposure to the cold in temperate humid climates. They are sometimes aggravated by sun exposure. Cold causes constriction of the small arteries and veins in the skin and rewarming results in leakage of blood into the tissues and swelling of the skin.

Chloracne

Chloracne is a rare acne-like skin condition caused by certain toxic chemicals including the dioxins. It develops a few months after swallowing, inhaling or touching the responsible agent.

Comedone Naevus

A comedone naevus is an unusual type of birthmark in which there is a localized collection of comedones. The cause is unknown. The comedones can arise from normal sized, enlarged or small sebaceous glands or even from sweat ducts. They may be found on any site of the body. Rarely, at puberty or later, a comedone naevus may develop inflammatory acne lesions within it.

Cryotherapy

Cryotherapy is a treatment in which skin lesions are frozen using liquid nitrogen or other cryogens. Cryotherapy is used for removing warts, seborrhoeic keratoses, solar keratoses (sun damage), and other benign lesions.

Cutaneous T Cell Lymphoma

(Mycoses Fungoides) CTCL is a term that applies to a T cell lymphoma first manifested in the skin. Occasionally, CTCL involves the blood, lymph nodes and internal organs. Often the initial rash is not specific and may resemble eczema for years before diagnosed. Treatments initially are very conservative and include light therapy and topical creams.

D

Dermatitis

The terms "dermatitis" and "eczema" are often used interchangeably. Dermatitis can be "acute" or "chronic" or both. Acute eczema refers to a rapidly evolving red rash, which may be blistered and swollen. Chronic dermatitis refers to a longstanding irritable area. It is often darker than the surrounding skin, thickened and much scratched. Dermatitis affects about one in every five people at some time in their lives. It results from a variety of different causes and has various patterns.

Dermatofibroma

A dermatofibroma is a common benign fibrous skin lesion. A dermatofibroma is also sometimes called a histiocytoma. The cause is unknown but some believe it arises at the site of a minor injury, especially an insect bite or thorn prick. Dermatofibromas most often occur on the legs and arms. Once developed, they usually persist for years. They appear as firm-feeling nodules, often yellow-brown in color, sometimes quite dark, especially in dark colored skin. If the skin over a dermatofibroma is squeezed a dimple forms, indicating tethering of the skin to the underlying fibrous tissue.

Dermatophytosis

Dermatophytosis is a type of fungal infection. These superficial infections are extraodinarily common and are more commonly known as jock itch, ringworm, or athlete's foot. They are caused by dermatophytes which are fungal organisms that live off the dead top layer of the skin (stratum corneun, nails and hair). These are usually treated with topical creams unless they are extensive or involve the hair or nails then requiring oral antibiotics for months.

Drug Eruption (rash)

These rashes can mimic virtually all of the many rashes that exist in Dermatology, and must be considered first on the differential diagnosis in the apperance of a sudden symmetrucal eruption. Drug eruptions are caused by both immunologic and nonimmunologic mechanisims and are provoked by the oral or topical administration of a drug.

Dry Skin

Dry Skin is clinically know as Xerosis. Which results from the loss of lipids (oils) in the skin and can occur with over bathing, advancing age, low humidity, and a result of drying from antibacterial and deodorant soaps. Some people have a genetic tendency towards dry skin.

E

Eczema

Eczema affects about one in every five people at some time in their lives. It results from a variety of different causes and has various patterns. The terms "dermatitis" and "eczema" are often used interchangeably. Dermatitis can be "acute" or "chronic" or both. Acute eczema refers to a rapidly evolving red rash, which may be blistered and swollen. Chronic dermatitis refers to a longstanding irritable area. It is often darker than the surrounding skin, thickened and much scratched. It is typically triggered by an irritating soap, hot water, a fragrance and even stress.

Erysipelas

Erysipelas is a sudden spreading infection of dermal and subcutaneous tissues (tissues underneath the skin) characterized by a red hot tender area of skin, often at the site of bacterial entry, caused most frequently by group A beta-hemolytic streptococci or staphylococcus aureus. Patients often have associated malaise, anorexia, fever, and chills.

Erythema Infectiosum

Erythema infectiosum is also known as Fifth disease. Fifth disease is a common childhood infection causing a "slapped cheek" appearance and a rash. It most commonly affects young children and often occurs in several members of the family or school class. Thirty percent of infected individuals have no symptoms. The child is usually otherwise quite well, but occasionally has a slight fever and headache. The first sign is firm red cheeks, which feel burning hot. A rash follows 1 to 4 days later with a lace or network pattern on the limbs and then the trunk. Although most prominent in the first few days, the rash can persist at least intermittently for up to six weeks.

Erythema Multiforme (minor)

This reaction pattern of small targetoid blisters on the hands and feet is often triggered by a herpes outbreak (cold sore). Typically lesions may occur on the lips and genitals. Treatment of the underlying infection results in resolution of the blisters.

Erythema Nodosum

Erythema Nodosum is an important acute inflammatory/immunologic reaction pattern of the fatty tissue under the skin, characterized by the appearance of painful tender nodules on the lower legs and caused by many etiologies including pregnancy, bacteria, drugs and sarcoidosis. Typically it has the appearance of raised bruises on the lower legs.

Erythrasma

Erythrasma is a common skin condition affecting the skin folds such as under the arms, in the groin and between the toes. The responsible organism is a bacterium, Corynebacterium minutissimum. It can infect anyone, but is particularly prevalent in those living in a warm climate. Erythrasma does not usually cause any symptoms. It presents as a slowly enlarging area of pink or brown dry skin.

Exfoliative Keratolysis

Exfoliative keratolysis is a common skin condition in which there is focal peeling of the palms and less often the soles. It is also known as keratolysis exfoliativa. Exfoliative keratolysis is more common during the summer months, and most often affects young adults. The first sign is one or more superficial air-filled blisters on the fingers or palms. The blisters burst to leave expanding collarettes of scale and circular or oval, tender, peeled areas. These peeled areas lack a normal barrier function and may become red, dry and cracked. However, they are not generally itchy. The symptoms are aggravated by exposure to irritants including water, soap, detergents and solvents. Eventually normal skin forms, but frequently exfoliative keratolysis recurs within a few weeks. Sometimes on the ends of the fingers the split in the skin is deeper, in which case the skin feels hard and numb and takes longer to peel off.

F

Fifth Disease

Fifth disease is a common childhood infection causing a "slapped cheek" appearance and a rash. It is also known as Erythema infectiosum. It most commonly affects young children and often occurs in several members of the family or school class. Thirty percent of infected individuals have no symptoms. The child is usually otherwise quite well, but occasionally has a slight fever and headache. The first sign is firm red cheeks, which feel burning hot. A rash follows 1 to 4 days later with a lace or network pattern on the limbs and then the trunk. Although most prominent in the first few days, the rash can persist at least intermittently for up to six weeks.

Fixed Drug Eruption

Fixed drug eruption is an adverse skin reaction to an ingested drug, characterized usually, as a solitary lesion which may burn and sometimes blister. Typically there is a bronze discoloration of the skin.

Flushing

Flushing occurs because the blood vessels in the skin dilate. There are various causes. When flushing is produced by activity of the nerves to the blood vessels it is accompanied by sweating. Agents, which act directly on the blood vessels, cause dry flushing.

Folliculitis

Folliculitis is the name given to a group of skin conditions with inflamed hair follicles. Causes of folliculitis includes, infections, irritation from regrowth of hair, contact reactions, inflammatory skin diseases, and acne variants.

Fungal Infections

These superficial infections are extraodinarily common and are more commonly known as jock itch, ringworm, or athlete's foot. They are caused by dermatophytes which are fungal organisms that live off the dead top layer of the skin (stratum corneun, nails and hair). These are usually treated with topical creams unless they are extensive or involve the hair or nails then requiring oral antibiotics for months.

G

Genital Herpes

Herpes simplex is one of the most common infections of mankind throughout the world. There are two main types of herpes simplex virus (HSV): type 1, which is mainly associated with facial infections and type 2, which is mainly associated with genital infections. These viruses cause lifelong infection with potential for reactivation or recurrence. Often people refer only to HSV-2 when discussing genital herpes but both types can cause infection in the genital area. Clinically, about 60-70% of primary genital infections are due to HSV-2 with the rest due to HSV-1. Both type 1 and type 2 herpes simplex viruses reside in a latent state in the nerves that supply sensation to the skin. With each episode of herpes simplex, the virus grows down the nerves and out into the skin or mucous membranes where it multiplies, causing the clinical lesion. After each episode it "dies back" up the nerve fiber and enters the resting state again.

Genital Warts

Genital warts are very common. They are caused by a virus, the human papillomavirus (HPV). Visible genital warts and sub clinical HPV infection nearly always arise from direct skin-to-skin contact. Transmission is common as genital warts often go unnoticed. Sub clinical infections can also be infectious. Often, warts will appear three to six months after infection but latency periods of many months or even years have been reported. Genital warts may occur in the following sites: Vulva, Vagina, Cervix, Urethra, Penis, Scrotum, Anus.

Gianotti Crosti Syndrome

The Gianotti Crosti Syndrome is a characteristic response of the skin to viral infection in which there is a papular rash which lasts for several weeks. Crosti Syndrome mainly affects children between the ages of 6 months and 12 years. A clustering of cases is often observed. A preceding upper respiratory infection is common. Over the course of 3 or 4 days a profuse eruption of dull red spots develops first on the thighs and buttocks, then on the outer aspects of the arms, and finally on the face. The rash is often asymmetrical. The individual spots are 5-10 mm in diameter and are a deep red color. Later they often look purple, especially on the legs, due to leakage of blood from the capillaries. Itch is uncommon, particularly if hepatitis B is the cause. The patient may feel quite well or have a mild temperature. Mildly enlarged lymph nodes in the armpits and groins may persist for months.

Gram Negative Folliculitis

Gram negative folliculitis is an acne-like disorder caused by a bacterial infection. Gram negative bacteria include Escherichia coli, Pseudomonas aeruginosa, Serratia marescens, Klebsiella and Proteus species. The term "Gram negative" refers to the staining pattern of the organisms in the laboratory. Gram negative folliculitis differs from acne in the following ways: Most of the lesions are pustules with relatively few papules and comedones and it may result from long-term treatment with tetracycline antibiotics.

Granuloma Annulare

Granuloma annulare is a common condition of unknown cause, which affects the skin of teenagers or young adults. In granuloma annulare (GA), skin colored bumps occur in rings often over joints, particularly the knuckles. The center of each ring is often a little depressed. It usually affects both hands, and limbs, symmetrically. It can occur on other sites of the body such as the abdomen or neck, and is occasionally quite widespread. Many patients have a cold hand or foot tendency. A few patients with extensive Granuloma Annulare have diabetes mellitus. Often it will disappear after a few weeks or months, but may recur.

H

Halo Nevi

A halo nevus is a mole with a white ring, or halo, around it and is sometimes known as Sutton's naevus or leukoderma acquisitum centrifugum. Halo moles are not uncommon and are usually seen in children or young adults of either sex. For reasons, which are unknown, the body selects a particular mole or moles for destruction. This is presumably because the mole is recognized as being abnormal in some way. The mole in the center of a halo is rarely malignant (cancerous) although all halo moles need to be examined carefully by an appropriate medical practitioner. Sometimes halo moles are triggered by sunburn, which damages the mole and causes it to be recognized by the body as foreign.

Head Lice

Head lice infest and cause itch and irritation in the scalp. This can take several weeks to develop after the initial infestation. Scratching can cause crusting and scaling on the scalp. Occasionally secondary bacterial infection of the scalp results in small sores on the scalp with tender glands in the neck. Dermatitis can also occur with a heavy infestation of lice. It is important to identify the lice (or nits) to make a correct diagnosis. Lice are around 3mm in length and can be seen moving from hair to hair. Unhatched eggs have a dark area within the shell while hatched eggs are transparent.

Hemangioma

A hemangioma (or angioma) is a small non-cancerous overgrowth of blood vessels in the skin. They occur in up to 10% of infants and can occur in adults as well. The Strawberry hemangioma, or Capillary Naevus, is more common in premature babies. The hemangioma may appear when the baby is a few days or weeks old and rapidly grow over a few months. The eventual size varies from a tiny dot to several centimeters in diameter. Occasionally hemangiomas bleed or ulcerate.

Herpes Simplex

Herpes simplex is one of the commonest infections of mankind throughout the world. There are two main types of herpes simplex virus (HSV); type 1, which is mainly associated with facial infections and type 2, which is mainly genital, although there is considerable, overlap. Both type 1 and type 2 herpes simplex viruses reside in a latent state in the nerves, which supply sensation to the skin. With each attack of herpes simplex the virus grows down the nerves and out into the skin or mucous membranes where it multiplies, causing the clinical lesion. After each attack it "dies back" up the nerve fiber and enters the resting state again. First attacks of type 1 infections occur mainly in infants and young children, which are usually mild or sub clinical. In crowded, undeveloped areas of the world up to 100% of children have been infected by the age of 5. In higher socioeconomic groups the incidence is lower, for example less than half of university entrants in Britain have been affected. Type 2 infections occur mainly after puberty, often transmitted sexually. The initial infection more commonly causes symptoms. The virus can be shed in saliva and genital secretions from individuals without symptoms, especially in the days and weeks following a clinical attack. The amount shed from active lesions is 100 to 1000 times greater. Spread is by direct contact with infected secretions. Minor injury helps inoculate the virus, especially into the skin. The virus can be inoculated into any body site to cause a new infection, whether or not there has been a previous infection of either type. The source of the virus may be from elsewhere on the body especially in nail biters or thumb suckers. Examples of inoculation from external sources include lesions of the hand in health-care workers, facial lesions contracted in rugby scrums, and infection of a breast-feeding mother's nipples from the infected mouth of her baby. Following the initial infection immunity develops but does not fully protect against further attacks. However where immunity is deficient, both initial and recurrent infections tend to occur more frequently and to be more pronounced.

Herpes Zoster

Shingles is a painful blistering rash caused by reactivation of Chicken Pox virus. Chickenpox (varicella) is the primary infection with the virus, Herpes zoster. During this widespread infection, which usually occurs in childhood, virus is "seeded" to nerve cells in the spinal cord, usually of nerves, which supply sensation to the skin. The virus remains in a resting phase in these nerve cells for years before it is reactivated and grows down the nerves to the skin to produce shingles (zoster). Shingles occurs sporadically. The annual incidence is about 3.4 per 1000. It is uncommon in childhood and the incidence increases with age. The sexes are equally affected. Shingles patients are infectious, both from virus in the lesions and in some instances the nose and throat. Susceptible contacts may develop chickenpox from exposure to the infected patient.

Hidradenitis Supporative

Hidradentis Supporative is a chronic pustular scarring disease of the apocrine (scent) glands of the armpits and groin. This starts at puberty and may last throughout life. Treatments include antibiotics, steroid injections, and ocassionally surgery to remove affected area.

Hirsutism

Hirsutism is the term used for increased hair growth in women. It refers to a male pattern of hair, i.e. in the moustache and beard areas, or occurring more thickly than usual on the limbs. There may be hairs on the chest or an extension of pubic hair on to the abdomen and thighs. What is considered normal for a woman, and what is considered hirsute, depends on cultural factors and race. Hirsutism is very common, and is often genetic in origin. Although some women with hirsutism have increased amounts of male hormone (eg. testosterone), most have normal levels. The problem in these women is that the hairs are more sensitive than normal to small amounts of hormone. The hairs grow more quickly and thicker in response to it. The increased hair growth is usually first noted in late teenage years and tends to gradually get more severe as the woman gets older. Blood tests may be arranged to make sure that the hirsutism is not due to excessive male hormone levels.

Hives

Hives are also know as Urticaria and refers to a group of disorders in which wealing occurs in the skin. The weals can be a few millimeters or several centimeters diameter, colored white or red, often surrounded by a red flare, and frequently itchy. Each weal may last a few minutes or several hours, and may change shape. Weals may be round, or form rings, a map-like pattern, or giant patches. The surface weals may be accompanied by deeper swelling of eyelids, lips, hands and elsewhere, called angioedema. Angioedema may occur without urticarial weals. The weals and swellings occur because of the release of chemicals, particularly histamine, into the tissues. This causes small blood vessels to leak, allowing fluid to accumulate in the skin. People often associate acute urticaria with an allergic reaction. Typically, medicines such as antibiotics, or food, including even tiny amounts of fish, eggs, nuts or chocolate, are responsible. It depends on previous exposure to the material, and the development of an immune reaction to it.

Hot tub folliculitis

Hot tub folliculitis is a skin infection that is caused by bacterial infection of the hair follicle. It arises hours to a few days after bathing in inadequately disinfected warm water, such as a hot tub, Jacuzzi or swimming pool. The result is an eruption of scattered small red itchy or tender bumps, some of which are pustular. They mainly occur in areas that were covered by the swimsuit.

Hyperhidrosis

Hyperhidrosis is the name given to excessive sweating. Hyperhidrosis may affect the entire body, or it may be localized to the armpits, palms or soles. Hyperhidrosis may occur in childhood or start later in life. Other family members may be similarly affected. An increase in air temperature, exercise, fever, anxiety, or spicy food may cause sweating. Sweating usually reduces at nighttime, but can continue throughout the day.

I

Ichthyosis

Ichthyoses refers to a group of mainly hereditary type of skin diseases where the skin resembles reptile scales. Occasionally, this condition occurs in patients with severe underlying disease such as cancer or tuberculosis.

Impetigo

Impetigo is a skin infection caused by bacteria. It is often called "school sores" because it affects children and is quite contagious. Streptococcus pyogenes and/or Staphylococcus aureus are the microorganisms responsible for impetigo. Impetigo most often occurs on exposed areas such as the hands and face. It presents with pustules and crusted oozing patches which grow larger day by day. Impetigo may be caught from someone else with impetigo or boils, or appear "out of the blue". It often starts at the site of a minor skin injury such as a graze, an insect bite, or scratched eczema.

Insect Bite reaction

After a bite there is usually a hive like reation where the skin becomes red, swollen, and itchy covering an area of less than 1 cm. This reaction may last for up to 2 weeks. Occasionally one or two bites may trigger dozens of lesions to come out all resembling the intial bite called papular urticaria. (see papular uticaria)

Intertrigo

Intertrigo is the word used to describe a yeast and bacterial infection involving body folds. Affected skin is reddened and uncomfortable. Intertrigo is particularly common in those who are overweight. Body folds (flexures) are prone to inflammatory rashes because of: Relatively high skin temperature; moisture from sweating; and friction from movement of adjacent skin. Bacteria and yeasts, which are normally resident on the skin, multiply in such environments and result in an irritated and macerated area of skin.

K

Keloids

Occasionally scars enlarge spontaneously to form firm, smooth, hard growths called keloids that may be uncomfortable or itchy, and may grow much larger than the original wound. If there is excessive tension on a healing wound, the healing area can thicken more than usual. This is known as a hypertrophic scar.

Keratoacanthoma

A keratoacanthoma is a variant of squamous cell carcinoma, which looks like a little volcano with a "core" in it. A keratoacanthoma (KA) often starts at the site of a minor injury to the skin, which has previously been damaged by the sun. At first it may appear as a small pimple or boil and may be squeezed but is found to have a solid core. It then grows rapidly and by the time it is brought to the attention of your doctor may be up to 2 cm in diameter.

Keratosis Pilaris

There are numerous tiny rough spots in the affected area. Each one is a horny plug, sometimes rather red but only rarely itchy and never sore. Keratosis Pilaris is a very common finding on the outer aspect of the upper arms of teenagers. It may occur in babies where it tends to be most obvious on the cheeks. It may remain for years but generally becomes less obvious in adult life; keratosis pilaris is uncommon in elderly people. Keratosis pilaris tends to be more severe during the winter months or other times of low humidity when skin dries out. It occurs because as the skin renews itself, old skin cells in the hair follicles get stuck, forming a scaly plug.

L

Latex Allergies

For reasons not yet clearly understood, some individuals can become allergic to certain constituents of the latex molecule. Once allergic, you may remain sensitive for the rest of your life. The common reactions of latex sensitive individuals exposed to latex are contact urticaria, dermatitis and asthma. Contact urticaria usually presents with itching and swelling of the skin at the site of contact with latex. This may, for example, be a hand from wearing gloves, genitals from contact with condoms, etc. The symptoms usually start within 5 - 15 minutes after coming into contact with the latex article, although it can be delayed for several hours. Symptoms can continue for a variable period, from several hours to days after the latex contact has ceased. Contact dermatitis from latex may take several days to appear. It presents with an itchy, scaly rash, although there may be small blisters if the reaction is acute. The rash will usually last several days to weeks but if exposure to latex continues, the rash will last longer. Contact dermatitis is not generally caused by sensitivity to latex protein but rather to the chemicals used in the manufacture of the latex product, including antioxidants and rubber accelerators e.g. thiuram, carbamates, MBT, etc. Immediate-type hypersensitivity requires previous sensitizations and is the most potentially dangerous reaction to latex. Clinical presentations vary but may include contact urticaria, coryza, conjunctivitis, stinging or burning, asthma, and, with mucosal or parenteral exposure, anaphylaxis. A common cause for the asthmatic reaction is powdered gloves. The starch powder picks up the latex proteins and when the gloves are removed the powders can then be inhaled or come into contact with the skin on the face where it can cause an allergic reaction.

Lentigo (sun spots)

These represent areas of permanent sun damage that pose no threat to the patient. They are areas of the skin in which the pigment producing cells (melanocytes) are damaged and typically overproduced pigment leading to so called "liver spots" or "age spots" on the hands face and chest. These can be successfully removed with a laser. Sometimes the opposite may occur and the melanocytes underproduce pigment resulting in a white spots.

Lentigo Maligna

Lentigo Maligna is a type of melanoma that arises on the face and can mimic a lentigo early in its course. This type of lesion makes it imperative that only a Dermatologist is qualified in the laser removal of pigmented (brown) spots.

Lichen Planus

Lichen planus is an inflammatory skin disease that is characterized by shiny violet colored very itchy bumps. Commonly affected areas include the wrists, ankles, penis and inside the mouth. The nails can also be affected. There is occasionally an association with hepatitis. Treatments include steroids, retnoids and light.

Lichen Simplex

Lichen simplex chronicus (neurodermatitis) is a common skin dermatitis that results from repeated rubbing or scratching of the skin. The stimulus to scratch may be unrecognized, perhaps a mosquito bite, stress, or simply a nervous habit. The result is a very itchy patch of skin, often located on the nape of the neck, scalp, shoulder, wrist, ankle, or genitals. The affected skin is thickened, often appearing as a group of small firm papules (bumps). The skin markings are more visible, and the hairs are often broken-off. The color may be darker or sometimes paler than the surrounding skin. Lichen simplex tends to be very persistent, and readily recurs despite often initially effective treatment.

Lupus

Lupus Erythematosis is an auto-immune disease in which the body's immune system attacks the nuclear proteins within the cells of the skin and other organs. Affected areas can result in permanent scarring, pigment loss and baldness. Treatment includes sunscreen, steroids, and immune altering medications.

Lyme Disease

Lyme disease is an infection caused by a spirochete transmitted by an infected deer tick. The intial rash resembles an expanding target or bull's eye around the bite. Untreated infection can lead to fever, arthritis, nerve involvement and heart disease. Thus early detection and prompt treatment is paramount.

M

Male Pattern Hair Loss

Male pattern hair loss is an inherited condition, caused by a genetically determined sensitivity to the effects of dihydrotestosterone, or DHT. DHT is believed to shorten the growth, or anagen, phase of the hair cycle, causing miniaturization of the follicles, and producing progressively finer hairs. An enzyme called 5-alpha reductase regulates the production of DHT. (see also Androgenetic Alopecia)

Melanoma

Melanoma is a serious skin cancer, which is curable if detected early. Melanoma grows from pigment cells (melanocytes) in the outer layer of the skin and mucous membranes (epidermis). Although melanoma usually starts as a skin lesion, occasionally it occurs in other parts of the body such as the eye, mouth or vagina. Melanoma tends to spread out within the epidermis before moving into the deeper layer of the skin (the dermis). It can occur in adults of any age.

Miliaria

Miliaria is an itchy rash, which arises from obstruction of the sweat ducts. Miliaria is most common in hot, humid conditions. The typical spots develop in skin folds and on the body, especially in areas of friction from clothing. The lesions present as minute red papules, which may be present in very large numbers. Once triggered miliaria can last for several weeks. This is because the plugs which form in the sweat duct openings can only be cast off by the outward growth of the sweat duct cells. This takes several weeks. Treatment cannot influence this process.

Moles (nevi)

Moles are common harmless skin lesions. Moles (melanocytic nevi) may be flat or protruding. They vary in color from pink flesh tones to dark brown or black. The number of moles a person has depends on genetic factors and on sun exposure. Moles begin to grow in infancy but new ones can appear at any age, sometimes in crops. Moles may darken following sun exposure or during pregnancy. During adulthood they often lose their pigmentation, and may disappear altogether in old age.

Molluscum Contagiosum

Molluscum contagiosum is a common viral skin infection resulting in small domed shaped bumps on the skin. Molluscum contagiosum resemble pimples at first. Later, when the spots enlarge, they often have a waxy, pinkish look with a small central pit. Sometimes there are as many as a hundred spots on one individual. Molluscum contagiosum can be spread to susceptible individuals by direct skin contact. It is harmless and never turns cancerous. It generally heals without scarring. Usually the lesions disappear within 9-12 months, rarely lasting longer than two years. They do, however, tend to be more numerous and last longer in children who also have atopic eczema.

Morphea

Morphea is a localized scarring of the skin characterized by a violet colored rash that evolves into an ivory colored firm depression. There is an associated loss of hair follicles and sweat glands. In Europe such lesions have been associated with a lyme disease-like infection.

Mucous Cyst

A mucous or myxoid cyst arises from degeneration in the connective tissue overlying the joints of the fingers. It may connect with the joint at the end of the finger. The cyst has a smooth shiny surface and is commonly found at the base of the nail. It often causes a groove in the nail, a few millimeters across which extends the length of the nail. The cyst's size may vary. Jelly-like sticky fluid may be expressed from it (sometimes tinged with blood).

N

Nail Fungal Infection

Fungal infection of the nails is known as "onychomycosis". It is increasingly common with increased age. It rarely affects children. Tinea unguium may affect one or more toenails and/or fingernails and most often involves the great toenail or the little toenail. It can present in one or several different patterns: Lateral onychomycosis, presenting with a white or yellow opaque streak at one side of the nail; Subungual hyperkeratosis, presenting with scaling under the nail; Superficial white onychomycosis, presenting with flakey white patches and pits appear on the top of the nail plate; and proximal onychomycosis, presenting with Yellow spots in the half-moon.

Nevi

Nevi is also known as a Mole. Moles are common skin lesions. Moles (correctly called melanocytic or pigmented nevi) may be flat or protruding. They vary in color from pink flesh tones to dark brown or black. The number of moles a person has depends on genetic factors and on sun exposure. Moles begin to grow in infancy but new ones can appear at any age, sometimes in crops. Moles may darken following sun exposure or during pregnancy. During adulthood they often lose their pigmentation, and may disappear altogether in old age.

Nickle Allergy

Contact allergic dermatitis to nickel may develop at any age. Once this nickel allergy has occurred, it persists for many years, often life-long. Nickel allergy is more common in women, probably because they are more likely to have pierced ears than men, although this is changing. The degree of allergy varies. Some people develop dermatitis (also called eczema) from even brief contact with nickel-containing items, while others break out only after many years of skin contact with nickel. Some people develop intermittent or persistent eczema on their hands and feet. It is usually a blistering type of eczema, known as pompholyx.

Nummular Eczema

Nummular dermatitis, also know as discoid eczema, is a skin condition which can occur at any age. It can affect any part of the body particularly the lower leg. One or many patches appear, and may persist for weeks or months. The majority of patches are round or oval, hence the name "discoid" or "nummular" dermatitis, which means coin or disc-shaped dermatitis. They can be several centimeters across, or as small as two millimeters. The skin between the patches is usually normal, but may be dry and irritable. Discoid eczema may be extremely itchy, or scarcely noticeable. When the patches clear, they may leave marks for some weeks of months, which are darker or sometimes paler than the normal skin tone. In most cases no specific allergy can be found. Discoid eczema does not run in families, and unlike atopic dermatitis, it is not associated with asthma. It does not result from food allergy. It is not infectious to other people, although bacteria sometimes secondarily infect it.

O

Occulusive Folliciltis

Occupational or therapeutic contact with mineral oils or tar can result in comedones and inflamed hair follicles (folliculitis). Excessive oil on the skin can result in small pustules with a red halo in affected areas. Commonly, the lesions are seen on the forearms and thighs. The follicles may obviously be plugged with oil. The pustules may be sterile or contain the harmless skin bacteria, Staphylococcus epidermidis. They may be painless or painful. Topical creams or ointments containing tar can also cause oil folliculitis. These are used for the treatment of eczema and psoriasis.

Onychomycosis

Fungal infection of the nails is known as "onychomycosis". It is increasingly common with increased age. It rarely affects children. Tinea unguium may affect one or more toenails and/or fingernails and most often involves the great toenail or the little toenail. It can present in one or several different patterns: Lateral onychomycosis, presenting with a white or yellow opaque streak at one side of the nail; Subungual hyperkeratosis, presenting with scaling under the nail; Superficial white onychomycosis, presenting with flakey white patches and pits appear on the top of the nail plate; and proximal onychomycosis, presenting with Yellow spots in the half-moon.

P

Palmoplantar Pustulosis

This condition is a variant of psoriasis in which groups of sterile pustules occur in crops on one or both hands and/or feet. They are associated with thickened, scaly, red skin, which easily develops painful cracks (fissures). The condition varies in severity and may persist for many years. It is not known what causes exacerbations or remissions. Palmoplantar pustulosis is not infectious to other people and does not influence one's general health. However the discomfort can be considerable, interfering with working and leisure activities. Walking for prolonged periods may cause exacerbations on the feet. If the palms are involved, manual activities may be uncomfortable, and injuries may aggravate the disorder. Certain occupations are therefore inadvisable for affected individuals. It is much more common in those who smoke (or have smoked in the past), sometimes runs in families and rarely occurs before adulthood.

Papular Urticaria

Papular urticaria is a skin condition, which most commonly affects children, and consists of crops of very itchy red bumps, 0.2 - 2 cm in diameter. The bumps may develop a fluid-filled blister up to one centimeter in diameter. They are most often on the legs and other uncovered areas such as forearms and face but sometimes they are scattered in small groups all over the body.

Pemphigoid

Pemphigoid (bullous pemphigoid) is an auto-immune disease in which the body produces antibodies to the basement membrane (the underlying layer of the skin) resulting in tense blisters. This condition tends to occur in older patients and occasionally related to medications.

Pemphigus

Pemphigus (pemphigus vulgaris) is an auto-immune disease in which the body produces antibodies to the skin cells in the epidermis resulting in flacid blisters of the skin and mucous membranes. This may result in serious complications and requires the use of oral immunosupressive drugs, including prednisone.

Perioral Dermatitis

Perioral dermatitis is a common disorder which manifests with groups of itchy or tender small red bumps around the mouth. They spare the skin bordering the lips (which then appears pale) and develop on the chin, upper lip and cheeks. The skin is often dry and flaky. The skin around the nose and eyes are sometimes affected.

Photosensitivity

Some people develop a rash because their skin is sensitive to sunlight; this is known as Photosensitivity. Patients may not associate their skin complaint with the light. It is not always the bright summer sun, which is responsible; some people also react to winter daylight, and very sensitive subjects may even be affected by fluorescent lamps indoors. Photosensitivity occurs for a variety of reasons. Some known causes include: Medicines taken internally. Chemicals, fragrances or plant materials in contact with the skin. A metabolic disorder such as Porphyria. Autoimmune disease (self-allergy), such as Lupus Erythematosus.

Phototherapy

Phototherapy is a treatment that consists of using light UVA and/or UVB range to treat numerous skin conditions. Disoeders commonly treated this modality include psoriasis, cutaneous t-cell lymphoma, and eczema.

Pitted Keratolysis

Pitted keratolysis is a skin condition affecting the soles of the feet. It affects those who sweat profusely (hyperhidrosis) especially if they wear occlusive shoes or boots for long periods. The condition is caused by Corynebacteria. Either the forefoot or the heel or both become white with clusters of punched-out pits. The appearance is more dramatic when the feet are wet. Very rarely, the fingers are similarly affected. There is a variant of pitted keratolysis where there are more diffuse red areas on the soles.

Pityriasis Alba

Pityriasis alba is a common skin condition affecting children and occasionally young adults. Several round or oval slightly scaly pink patches appear, leaving pale marks when the redness has faded. Pityriasis alba patches are more apparent in summer, especially in dark-skinned children, because they don't tan as well as the surrounding skin. Pityriasis alba is a mild form of dermatitis of unknown cause. It will clear up after a few months, or in some cases persist two or three years. The color gradually returns completely to normal.

Pityriasis Rosea

Pityriasis rosea is a common viral infection of the skin which is characterized by pink to red oval rose petal shaped lesions on the torso, arms, and legs sparing the hands, feet and face. Typically, there is an intial "herald patch" which precedes the generalized rash. There maybe some itchiness associated with it and it can be treated with steroid creams and light therapy. It typically occurs only once in a lifetime.

Pityrosporum Folliculitis

Pityrosporum folliculitis is a condition where the yeast, pityrosporum (also called Malassezia furfur), infiltrates the hair follicles and multiplies, creating an itchy, acne-like eruption. The condition affects young to middle-aged adults of either sex. It is associated with a tendency to seborrhoeic eczema or severe dandruff. The rash consists of tiny itchy dome-shaped pink papules with an intermingling of small pustules. The spots are located mainly on the upper back, shoulders and chest. Occasionally, spots are found on the forearms, back of the hands, lower legs and face.

Plant Dermatitis

Plant dermatitis is an eruption caused by skin contact with certain plants. The rash may take various forms but is generally itchy, red and swollen. Common offending plants include poison ivy, Peruvian lily, and English primrose. Some plants only cause a rash if the sun is shining on the skin at the same time (phytophotodermatitis). Plant dermatitis is not contagious and the blister fluid does not spread the rash. The rash appears between four hours and 10 days after exposure to the plant, depending on individual sensitivity and the amount of contact. Occasionally, new eruptions can appear after treatment has begun due to blood stream spread of the allergy to other areas.

Pompholyx

Pompholyx is also known as, vesicular hand and/or foot eczema. It is a common type of eczema affecting the hands (cheiropompholyx), and sometimes the feet (pedopompholyx). The condition may be mild with subtle peeling, or severe with large blisters and cracks. The first (acute) stage presents with tiny blisters (vesicles) deep in the skin, associated with itching and a burning feeling. The more chronic stage manifests with more peeling, cracking, or crusting. Some patients will have mostly one stage, and some patients will have mostly the other. Some times both stages occur at the same time. Secondary infection with Staphylococcal bacteria is not infrequent. The result is pain, redness, swelling and crusting or pustules. Pompholyx of the hands is aggravated by contact with irritants such as water, detergents and solvents. Contact with these agents must be avoided as much as possible and protective gloves worn.

Porphyria Cutanea Tarda

Porphyria cutanea tarda is the most common type of porphyria. Prophyria cutanea tarda (PCT) is due to a defective enzyme in the liver (uroporphyrinogen decarboxylase) involved in synthesis of the red pigment in blood cells (heme). The result is an increase in porphyrins in the skin, resulting in photosensitivity i.e. the skin is damaged by light. Affected individuals develop fragile skin, sores (erosions), blisters (vesicles and bullae), and tiny cysts (milia) on the sun-exposed areas i.e. the back of the hands and the forearms. They may notice that they sunburn easily. Some people develop mottled brown patches around the eyes and increased facial hair. Occasionally the skin becomes hardened (sclerodermoid) on the neck, face or chest. There may be small areas of permanent baldness (alopecia) or ulcers. There is a genetic predisposition to PCT. It generally begins in mid-adult life after exposure to certain chemicals, which increase the production of porphyrins (precursors of heme) in the liver.

Pseudofolliculitis Barbae

Pseudofolliculitis barbae is also known as shaving rash or razor bumps. It is a foreign-body inflammatory reaction surrounding ingrown facial hair, which results from shaving. The problem occurs more commonly in individuals with curly hair.

Psoriasis

Psoriasis is a disorder of the skin, which typically consists of red plaques covered by silvery-white scales. These red scaly patches are usually found on the elbows, knees, lower back, and scalp. When psoriasis involves the groin, armpits, and genital area and beneath the breasts it tends to be less scaly and have a glazed appearance. Psoriasis infrequently affects the face. It does not cause scarring and rarely results in hair loss. Psoriasis is common, affecting approximately 2% of adults. Its exact cause is unknown but the result is skin, which grows about seven times quicker and thicker than usual. It is thought to be due, at least in part, to an abnormal immune reaction against some component of the skin. Genetic factors play a part; only some families develop the condition, and about half those affected know of someone else in the family with it. The rash often seems to start after some sort of trigger factor. This may be emotional stress, skin injury (cuts and scratches for example), a streptococcal sore throat, hormones (it often first occurs at puberty), or rarely, certain medications. These factors should be avoided whenever possible by people with psoriasis. Psoriasis is not an allergy, nor is it infectious to others.

R

Rosacea

Rosacea is a facial rash that occurs in middle-aged men and women. It is tought to be related to an overgrowth of a mite that normally resides on the skin. Rosacea affects people mainly in the 30s and 40s, especially those with fair-skin, blue eyes and of Celtic origin. Rosacea used to be called "acne rosacea" but it is quite different from acne. The red spots and pustules are dome-shaped rather than pointed and there are no blackheads, whiteheads, deep cysts, or lumps. Sometimes the affected skin is swollen and hot. Rosacea affects the cheeks, nose and forehead , rarely it involves the trunk and upper limbs. Facial creams or oils, and topical steroids may aggravate it.

S

Scabies

Scabies is an itchy skin condition caused by a mite that burrows in the surface of the skin. Scabies is acquired by skin-to-skin contact with an infected person. The contact may be quite brief such as holding hands. Scabies causes a severely itchy rash with tiny lumps, blisters and "burrows" in characteristic sites on the skin. These include between the fingers, around the wrists, around the armpit folds, buttocks, on the penis in the male, insteps of the feet, and backs of the heels. Surprisingly, scabies only rarely affects the face and head. Itchy nodules (small lumps) on the penis are almost always due to scabies and such nodules on the buttocks and around the armpits are also very suggestive. One may have scabies for up to 12 weeks before there is any itch or rash. The itch of scabies is due to an allergy to the mites and their products, which takes at least 4 weeks to develop. During this time, a patient can be infested with scabies, and passing it on to others, without any symptoms.

Scalp Folliculitis

Scalp folliculitis is an inflammatory disorder of hair follicles in the scalp. The condition is also known as "acne necrotica miliaris" or "Proprionibacterium acnes" folliculitis. It is characterized by small, very itchy pustules within the scalp.

Schamberg's Disease

This is the most common type of Capillaritis (reddish -brown patches caused by leaky capillaries) Crops of red-brown flat patches with cayenne pepper spots on their borders appearr for no apparent reason. Although it is most common on the lower legs, Schamberg's can arrise on any part oh the body. It is usually distributed on both sides with few or many patches.

Scleroderma

Morphea is a localized scarring of the skin characterized early by a violet colored rash and later by an ivory colored depression wich is hard. There is an associated loss of hair follicles and sweat glands. In Europe such leasions have been associated with a lyme disease-like infection. There is no effective treatment.

Sebaceous Hyperplasia

Sebaceous hyperplasia is the term used for enlarged sebaceous glands seen on the forehead or cheeks of the middle-aged and elderly. They are sometimes confused with basal cell carcinoma. Sebaceous hyperplasia appears as small yellow bumps up to 3 mm in diameter. Close inspection reveals a central hair follicle.

Seborrhea

Seborrhea is the name given to excessively oily skin. It is due to overactive sebaceous glands and can affect both males and females. The oil produced by the skin is called sebum. Although most people with seborrhea have no other health problems, it is sometimes a sign of underlying disorders. The skin feels unpleasant, and seems to get dirty quickly. The face appears shiny. Make-up may run off or cake. Seborrhea can also result in acne or seborrhoeic dermatitis.

Seborrhoeic Dermatitis

Seborrhoeic dermatitis is a common, harmless, scaling rash that sometimes itches. Dandruff (also called pityriasis capitis) is seborrhoeic dermatitis of the scalp. Seborrhoeic dermatitis may also occur on the eyebrows, eyelid edges, ears, the skin near the nose and skin-folds of the armpits and groin. Sometimes seborrhoeic dermatitis produces round, scaling patches on the middle of the chest or on the back. Seborrhoeic dermatitis is believed to be due to a proliferation of a normal skin inhabitant, a yeast called Pityrosporum ovale (Malassezia furfur). Patients with seborrhoeic dermatitis appear to have a reduced resistance to the yeast due to various factors including stress, fatigue, change of the seasons and reduced general health. It is not contagious or related to diet. Nervous stress and any physical illness tend to worsen the condition.

Seborrhoeic Keratoses

Seborrhoeic keratoses are harmless common skin growths that first appear during adult life. Seborrhoeic keratoses may also be called basal cell papillomas, senile warts or brown warts. As time goes by, seborrhoeic keratoses become more numerous. Some people have inherited a tendency to develop a very large number of them. Seborrhoeic keratoses appear on both covered and uncovered parts of the body; they are not generally caused by sunlight, although they can follow sunburn or other irritating skin conditions including dermatitis. Seborrhoeic keratoses are harmless and rarely become malignant. They begin as slightly raised, light brown spots. Gradually they thicken and take on a rough, warty surface. They slowly darken and may turn black. These color changes are harmless. Seborrhoeic keratoses are superficial and look as if they were stuck on the skin. People who have had several seborrhoeic keratoses can usually recognize this type of benign growth.

Shingles (herpes zoster)

Shingles is a painful blistering rash caused by reactivation of Chicken Pox virus. Chickenpox (varicella) is the primary infection with the virus, Herpes zoster. During this widespread infection, which usually occurs in childhood, virus is "seeded" to nerve cells in the spinal cord, usually of nerves, which supply sensation to the skin. The virus remains in a resting phase in these nerve cells for years before it is reactivated and grows down the nerves to the skin to produce shingles (zoster). Shingles occurs sporadically. The annual incidence is about 3.4 per 1000. It is uncommon in childhood and the incidence increases with age. The sexes are equally affected. Shingles patients are infectious, both from virus in the lesions and in some instances the nose and throat. In susceptible contacts of shingles, chickenpox, sometimes severe, can occur. The first sign of shingles is usually pain, which may be severe, and may be accompanied by fever, headache, feeling unwell and tenderness localized to the areas of one or more sensory nerves where they emerge from the spine. The pain may be sharply localized to the same area or may be more diffuse. The time between the start of the pain and the onset of the eruption averages 1.4 days in shingles of the face and 3.2 days in trunk shingles. Closely grouped red papules, rapidly becoming blistered and then pustular, develop in a continuous band in the area of skin supplied by one, occasionally two, and, rarely more neighboring spinal nerves. Inside of the mouth can also be involved. New vesicles (blisters) continue to appear for several days.

Solar comedones

Solar comedones arise on the face of the middle-aged and elderly. They affect areas that have been exposed to sunlight over a long period of time, particularly the cheeks, which may become yellow and "leathery" (solar elastosis). The comedones may be "open" (blackheads) or "closed" (whiteheads). There may be larger cysts. Solar comedones are not related to acne vulgaris and do not usually become inflamed. They are however very persistent.

Solar Keratoses (Actinic Keratoses)

Rough scaly spots on sun-damaged skin are called solar keratoses. Solar keratoses are caused by repeated sun exposure damages the skin, especially in fair-skinned persons. Sun-damaged skin is dry and wrinkled and may form persistently scaly spots, solar (actinic) keratoses, even though the crust or scale is picked off.

Squamous Cell Carcinoma

Squamous cell carcinoma is a common skin cancer that typically affects people of fair complexion. Lesions develop in areas that have been exposed to the sun over a long period. Squamous Cell Carcinomas vary in size from a few millimeters to several centimeters in diameter. Sometimes they grow to the size of a pea or larger in a few weeks, though more commonly they grow slowly over months or years. They may be tender. Some SCCs appear as sores, which fail to heal. A common site is the bottom lip - if a sore has not gone in 3 weeks, get it checked. SCCs are often crusty and may bleed easily. Early SCC is known as Bowen's disease. This is a flat red scaly patch up to several centimeters wide, often found in large numbers on the lower legs. The development of a lump or bleeding in Bowen's disease may indicate the beginning of invasive SCC.

Steroid Acne

Steroid acne is an acne-like skin condition that follows the use of steroid medications. Steroid acne most often occurs on the chest but may also develop on the face, neck, back and arms. It most often affects adolescent or adult patients who have been taking moderate or high doses of oral steroids for several weeks. Steroid acne presents with small skin bumps, which may itch. Sometimes they are pustular. Unlike acne vulgaris, most of the lesions are similar in size. Nodules are rare.

Steroid Rosacea

Steroid rosacea is the name given to a rosacea-like condition on the face caused by potent topical steroids. After several weeks of applying a topical steroid to the eyelids, cheeks or chin the affected area becomes red. Small bumps (papules) and pustules appear intermittently, and may paradoxically worsen when the topical steroid cream is discontinued.

Syphilis

Syphilis is a sexually transmitted infection caused by the spirochete treponenum pallidumcharacterized by the appearance of a painless ulcer or chancre at the site of inoculation often associated with enlarged lymph nodes in the vicinity. Shortly after inoculation, syphilis becomes a systematic infection. Untreated syphilis can affect virtually any organ including the brain.

T

Tinea

The term "tinea" refers to a skin infection with a dermatophyte (ringworm) fungus. (See Dermatophyte)

Tinea Nigra

Tinea nigra affects the skin of the palm and/or sole with persistent slowly growing brown or black patches. They are slightly scaly and do not itch or sting. Tinea nigra is most common in tropical regions and often infects those with a tendency to excessive sweating (hyperhidrosis). Tinea nigra is due to infection with a brown mould, Exophiala phaeoannellomyces. This mold usually inhabits soil.

Tinea Versicolor

Tinea versicolor is a harmless skin disorder caused by a yeast, Malassezia furfur, which may be found on normal skin. This yeast usually grows sparsely without causing any symptoms. For unknown reasons, it grows more actively in certain individuals. This results in pale brown flaky patches on the trunk, neck, or arms. Tinea versicolor is pink or coppery in pale subjects, but on tanned skin the patches are lighter, since tanning does not occur in the affected areas. The yeast produces a chemical, which diffuses down and impairs the function of the pigment cells in the underlying skin. The failure to tan is temporary; the skin tans normally with sun exposure after the rash has cleared up. Tinea versicolor is generally not contagious. It is more common in hot, humid climates or in those who sweat heavily, so it may recur each summer.

Trichoepithelioma

Trichoepithelioma is the name given to an uncommon condition in which a single lesion or multiple benign tumors (harmless skin growths) arise on the face after puberty. The tumor cells form rudimentary hair follicles but do not form actual hair shafts. The tendency to multiple Trichoepithelioma is inherited but the condition is more common in females. The tumors are small (usually less than one centimeter), firm, rounded and shiny. They may be yellow, pink, brown or bluish. They usually gradually increase in number with age, occurring on both cheeks, eyelids and around the nose.

Trichostasis Spinulosa

Trichostasis spinulosa consists of numerous tiny open pores filled with multiple tiny short hairs, usually only visible with a magnifying glass. Trichostasis spinulosa affects the skin of the nose of adults, and is often confused with blackheads.

U

Ulcers

Ulcers are produced by the breakdown of skin leading to weeping open wounds. They are commonly seen with compromised blood flow of the lower legs.

Urticaria (hives)

Urticaria refers to a group of disorders in which wheals occurs in the skin. The wheals can be a few millimeters or several centimeters diameter, colored white or red, often surrounded by a red flare, and frequently itchy. Each wheal may last a few minutes or several hours, and may change shape. Wheals may be round, or form rings, a map-like pattern, or giant patches. The surface wheals may be accompanied by deeper swelling of eyelids, lips, hands and elsewhere, called angioedema. Angioedema may occur without urticarial wheals. The wheals and swellings occur because of the release of chemicals, particularly histamine, into the tissues. This causes small blood vessels to leak, allowing fluid to accumulate in the skin. People often associate acute urticaria with an allergic reaction. Typically, medicines such as antibiotics, or food, including even tiny amounts of fish, eggs, nuts or chocolate, are responsible. It depends on previous exposure to the material, and the development of an immune reaction to it.

UVB Phototherapy

UVB phototherapy refers to irradiation with short wave ultraviolet radiation.

V

Varicella (chickenpox)

Varicella is a highly contagious primary infection caused by the herpes varicella-zoster virus, characterized by sucessive crops of itch small blisters which can evolve into pustules, crusts and even scars. There is often associated headache, fever, generalized aches, and malaise. In adults the disease is usually more severe and may lead to pneumonia, encephalitis and myocarditis.

Vasculitis

Vasculitis refers to inflamation of the blood vessels in the skin. Typically this may represent an allergic reaction to medication or infection or less often may represent an auto-immune disease. Vasculitis manifests as small bruises under the skin which may be bright red to purple. It is more commonly seen on the legs, but may involve multiple organ sstems. The more common allergic type usually resolves when offending drug, infection, or tumor is removed.

Verruca Vulgaris

Warts are tumors or growths of the skin caused by infection with Human Papilloma Virus. More than 70 Human Papilloma Virus (HPV) subtypes are known. Those on the sole of the foot are generally known as "verrucas", or plantar warts. Warts are very common in childhood and are spread by direct contact or autoinocculation.

Vitiligo

Vitiligo is a condition in which pigment cells are destroyed by cells of the immune system, resulting in irregularly shaped white patches on the skin. Any part of the body may be affected. Common sites are exposed areas (face, neck, eyes, nostrils, nipples, navel, genitalia), body folds (armpits, groin). Also, sites of injury (cuts, scrapes, burns), around pigmented moles, hair (early greying of hair on scalp and body), and the retina.

W

Warts

Warts are tumors or growths of the skin caused by infection with Human Papilloma Virus. More than 70 Human Papilloma Virus (HPV) subtypes are known. Warts are very common in childhood and are spread by direct contact or autoinocculation. This means if a wart is scratched, the viral particles may be spread to another area of skin. It may take as long as twelve months for the wart to appear. In children, 50% of warts disappear on their own within 6 months, and 90% are gone in 2 years. They tend to be more persistent in adults, lasting 5-7 years, but always go eventually.

X

Xerosis (dry skin)

Xerosis results from the loss of lipids (oils) in the skin and can occur from over bathing, advancing age, low humidity , and a result of drying from antibacterial and deodorant soaps. Some people have a genetic tendency towards dry skin.

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