Glossary - Dermatology
acne - a chronic disorder of the hair follicles and sebaceous glands. Acne is characterized by black heads, pimple outbreaks, cysts, infected abscesses, and (sometimes) scarring.
albinism - a rare, inherited disorder characterized by a total or partial lack of melanin (skin pigment) in the skin.
alopecia - baldness.
angioma - a benign tumor in the skin, which is made up of blood or lymph vessels.
atopic dermatitis (Also called eczema.) - a skin disorder that is characterized by itching, scaling, thickening of the skin, and is usually located on the face, elbows, knees, and arms.
atrophic skin - skin that is thin and wrinkled.
basal cell carcinoma - the most common form of skin cancer; characterized by small, shiny, raised bumps on the skin that may bleed.
basal cells - type of cells that are found in the outer layer of skin. Basal cells are responsible for producing the squamous cells in the skin.
birthmark - abnormality of the skin that is present at birth or shortly afterward.
bed sores - ulcers that occur on areas of the skin that are under pressure from lying in bed, sitting in wheelchairs, wearing a cast, or being immobile for a long period of time.
biopsy - a procedure performed to remove tissue or cells from the body for examination under a microscope.
blister - a fluid-filled bump.
boil - tender, swollen areas that form around hair follicles.
botulinum toxin type A - an injection of botulinum toxin into specific muscles will immobilize those muscles, preventing them from forming wrinkles and furrows.
candidiasis (Also called yeast infection.) - a skin infection caused by yeast that can occur in the skin folds, navel, vagina, penis, mouth, and nail beds.
carbuncles - clusters of boils on the skin.
cavernous hemangioma - a raised, red or purple mark in the skin, made up of enlarged blood vessels.
cellulitis - a bacterial infection of the skin that is characterized by swelling and tenderness.
chemical peels - a procedure often used to minimize sun-damaged skin, irregular pigment, and superficial scars. The top layer of skin is removed with a chemical application to the skin. By removing the top layer, the skin regenerates, often improving the skin's appearance.
cold sore - small blisters around and in the mouth caused by the herpes simplex virus.
collagen - a natural protein found in humans that forms connective tissue and provides strength, resilience, and support to the skin, ligaments, tendons, bones, and other parts of the body.
collagen injections - one type of collagen, which is derived from purified bovine (cow) collagen, is injected beneath the skin to replace the body's natural collagen that has been lost. Injectable collagen is generally used to treat wrinkles, scars, and facial lines.
creeping eruption - a skin infection caused by hookworms that is characterized by severe itching.
crust (Also called scab.) - a formation of dried blood, pus, or other skin fluid over a break in the skin.
cryosurgery - destruction of a lesion on the skin by freezing with liquid nitrogen.
cyst - a deep lesion that is filled with pus or other contents.
dermabrasion - used to minimize small scars, minor skin surface irregularities, surgical scars, and acne scars. As the name implies, dermabrasion involves removing the top layers of skin with an electrical machine that "abrades" the skin. As the skin heals from the procedure, the surface appears smoother and fresher.
dermatitis - a number of skin conditions characterized by inflammation of the skin.
dermatofibroma - small, red or brown bumps in the skin.
dermis - the middle layer of skin, which is made up of blood vessels, lymph vessels, hair follicles, sweat glands, collagen bundles, and fibroblasts.
dermoid cyst - a benign tumor made up of hairs, sweat glands, and sebaceous glands.
eczema (Also called atopic dermatitis.) - a skin disorder that is characterized by itching, scaling, thickening of the skin, and is usually located on the face, elbows, knees, and arms.
epidermis - the outermost layer of skin.
erysipelas - a bacterial skin infection that usually affects the arms, legs, or face, characterized by shiny, red areas, small blisters, and swollen lymph nodes.
erythema multiforme - a skin condition characterized by symmetrical, red, raised skin areas all over the body.
erythema nodosum - a skin condition characterized by red bumps that usually appear on the shins.
erythrasma - a skin infection of the top layer of skin characterized by irregular pink patches that turn to brown scales.
exanthem - a rash.
excoriation - an area of the skin covered by a crust, or scab, usually caused by scratching.
folliculitis - an inflammation of the hair follicles due to an infection or irritation.
freckles - darkened, flat spots that typically appear only on sun-exposed areas of skin.
granuloma annulare - a chronic skin condition characterized by small, raised bumps that form a ring with a normal or sunken center.
herpes zoster (Also called shingles.) - a common viral infection of the nerves, characterized by a painful skin rash of small blisters anywhere on the body.
hirsutism - excessive hairiness.
hives (Also called urticaria.) - a condition in which red, itchy, and swollen areas appear on the skin usually as an allergic reaction from eating certain foods or taking certain medications.
immune system - a collection of cells and proteins that works to protect the body from potentially harmful, infectious microorganisms, such as bacteria, viruses, and fungi.
immunocompromised - an abnormal condition in which one's ability to fight infection is decreased. This can be due to a disease process, certain medications, or a condition present at birth.
impetigo - a bacterial skin infection characterized by microscopic, pus-filled blisters.
inflammation - redness, swelling, heat, and pain in a tissue due to chemical or physical injury, infection, or allergic reaction.
keloids - smooth, pink, raised, firm, fibrous growths on the skin that form secondary to injury.
keratinocytes (Also called squamous cells.) - the primary cell types found in the epidermis, the outer layer of skin.
keratoacanthomas - round, flesh-colored growths with craters that contain a pasty material.
keratosis pilaris - a common skin condition characterized by small, pointed bumps, especially on the back and sides of the upper arms.
laser resurfacing - uses high-energy light to burn away damaged skin. Laser resurfacing may be used to minimize wrinkles and fine scars.
lice - tiny parasites that can infest the skin; characterized by intense itching.
lichenification - skin that has thickened.
lipomas - round or oval lumps under the skin caused by fatty deposits.
lymphangioma - a raised, yellow-tan or red mark in the skin, made up of enlarged lymphatic vessels.
macular stains (Also called angel's kisses or stork bites.) - faint, red marks that appear in the skin at birth. Angel's kisses are marks on the forehead and eyelids. Stork bites are marks on the back of the neck.
macule - the smaller version of a patch - a flat discolored spot.
malignant melanoma - a rare, but sometimes deadly, skin cancer that begins as a mole that turns cancerous.
melanocytes - cells present in the epidermis that produce melanin (skin pigment).
melasma - dark, brown symmetrical patches of pigment on the face.
moles - small skin marks caused by pigment-producing cells in the skin.
Mongolian spots - Bluish-black marks on the lower back and buttocks; affects mainly African-American or Asian children.
nodule (Also called papule.) - a solid, raised bump.
paronychia - a skin infection around a finger or toenail.
patch - a flat, discolored spot.
pityriasis rosea - a common skin condition characterized by scaly, pink, and inflamed skin.
port-wine stains (Also called nevi flammeus.) - permanent flat, pink, red, or purple marks on the skin.
prickly heat - a rash caused by trapped sweat under the skin.
psoriasis - a chronic skin condition characterized by inflamed, red, raised areas that develop silvery scales.
punch grafts - small skin grafts to replace scarred skin. A hole is punched in the skin to remove the scar, which is then replaced with unscarred skin (often from the back of the earlobe). Punch grafts can help treat deep acne scars.
pustule (Also called pimple.) - inflamed lesions that look like pink bumps.
pyogenic granuloma - red, brown, or bluish-black raised marks caused by excessive growth of capillaries.
ringworm - a fungal skin infection characterized by ring-shaped, red, scaly, or blistery patches.
rosacea - a common skin condition characterized by redness, pimples, and broken blood vessels.
salicylic acid - a keratolytic drug (a drug that removes the outer layer of skin) that is used to treat various skin conditions.
sarcoidosis - an inflammation of the lymph nodes and other organs.
scabies - an infestation of mites in the skin characterized by small pimples that itch.
scales - dead skin cells that look like flakes or dry skin.
scar - fibrous tissue that has formed after a skin injury.
sebaceous glands - glands in the skin that secrete oil to the surface of the skin.
seborrheic keratosis - flesh-colored, yellow, brown, or black wart-like spots.
skin tags - soft, small, flesh-colored skin flaps on the neck, armpits, or groin.
spider angioma - a bright red mark with a distinct dark spot in the skin.
squamous cells (Also called keratinocytes.) - the primary cell types found in the epidermis, the outer layer of skin.
squamous cell carcinoma - a form of skin cancer that affects about 20 percent of patients with skin cancer. This highly treatable cancer is characterized by red, scaly skin that becomes an open sore.
subcutis - the deepest layer of skin; also known as the subcutaneous layer.
tinea versicolor - a common fungal skin infection characterized by white or light brown patches on the skin.
toxic epidermal necrolysis - a life-threatening skin disorder characterized by blistering and peeling of the top layer of skin.
tretinoin - a drug which is chemically related to vitamin A; used to treat acne and other scaly skin disorders.
trichotillomania - hair pulling.
urticaria (Also called hives.) - a condition in which red, itchy, and swollen areas appear on the skin usually as an allergic reaction from eating certain foods or taking certain medications.
urushiol - resin in poison ivy plants that causes an allergic skin reaction.
vitiligo - smooth, white patches in the skin caused by the loss of pigment-producing cells.
wart - a non-cancerous skin growth caused by a virus.