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.
Angioma - a benign tumor in the skin, made up of blood or lymph vessels.
Basal cell carcinoma - the most common form of skin cancer, characterized by small, shiny, raised bumps on the skin that are fragile and often bleed.
Basal cells - these cells 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.
Biopsy - when a sample of tissue is removed for examination under a microscope.
Blister - a fluid-filled bump.
Boil - tender, swollen areas that form around hair follicles.
Candidiasis (also called yeast infection) - a skin infection caused by yeast that can occur in the skin folds, the 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 burns - burns due to strong acids or alkalies coming into contact with the skin and/or eyes.
Cold sore - recurrent, small blisters around and in the mouth caused by the herpes simplex virus.
Collagen - a protein produced by skin cells that provide strength and resilience to the skin.
Congenital - present at birth.
Contact dermatitis - a rash or an inflammation of the skin caused by contact with various substances.
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.
Dermatitis - a number of skin conditions characterized by inflammation of the skin.
Dermatofibroma - slow growing small, red or brown papules or nodules in the skin.
Dermis - the middle layer of skin, which is made up of blood vessels, lymph vessels, hair follicles, and sweat glands.
Dermoid cyst - a benign tumor made up of hairs, sweat glands, and sebaceous glands.
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.
Electrical burns - burns due to contact with an electrical current.
Epidermis - the outer layer of skin, which is made up of the horny layer, squamous cells, and basal cells.
Erythema nodosum - a skin condition, characterized by painful 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.
First-degree burns (also called superficial burns) - burns that only affect the epidermis, or outer layer of skin. The burn site appears red, painful, dry, and absent of blisters. Mild sunburn is an example. Scarring is usually rare or minimal.
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. It is a reactivation of chickenpox virus.
Hives - see urticaria.
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 where 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.) - these are the primary cell types found in the epidermis - the outer layer of skin.
Keratosis pilaris - a common skin condition characterized by small, pointed bumps especially on the back and sides of the upper arms.
Kerion - a large inflamed tender lesion that is a complication of ringworm of the scalp.
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 - Skin cancer that originates in skin cells that produce pigment, melanocytes.
Melanocytes - cells present in the epidermis that produce melanin (skin pigment).
Melasma - dark, brown, symmetrical patches of pigment on the face that result from sun exposure.
Meningitis - an inflammation of the covering of the brain and spinal cord.
Moles - small skin marks caused by pigment-producing cells in the skin.
Mongolian spots - Bluish-black marks on the lower back and buttocks and are present at birth; 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 that often appears on the body in a Chirstmas tree-like pattern.
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 that can occur anywhere on the body but mostcommonly on the scapl, elbows, and knees.
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.
Radiation burns - burns due to prolonged exposure to ultraviolet rays of the sun, or to other sources of radiation such as x-ray.
Ringworm - a fungal skin infection characterized by ring-shaped, red, scaly, or blistery patches.
Rosacea - a common facial 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.
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.
Second-degree burns (also called a partial thickness burn) - burns that involves the epidermis and part of the dermis layer of skin. The burn site is red, blistered and painful, with possible swelling.
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 cell carcinoma - the second most common 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.
Squamous cells - see keratinocytes.
Subcutis - the deepest layer of skin; consists of collagen and fat cells.
Thermal burns - burns due to external heat sources which raise the temperature of the skin and tissues and cause tissue cell death or charring. Hot metals, scalding liquids, steam, and flames, when coming in contact with the skin, cause thermal burns.
Third-degree burns (Also called a full thickness burn.) - burns that destroy the epidermis and dermis. The burn site appears white or charred black. There is no sensation in the area, because the nerve endings are destroyed.
Thrush - a fungal infection of the mouth that usually causes a white coating on the tongue, cheeks or throat.
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.
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.
Verruca vulgaris - common wart.
Viral exanthem - eruption or rash following a viral illness.
Vitiligo - smooth, white patches in the skin caused by the loss of pigment-producing cells.
Wart - a noncancerous skin growth caused by a virus.
Xanthoma - a colored papule or nodule associated with a high cholesterol level.
Xerosis - dry skin.