Glossary

Acne conglobata: A very severe type of acne in which nodules are connected beneath the skin surface to other nodules or acne lesions.

Acne mechanica:  Form of acne that develops in response to heat, covered skin, constant pressure, and/or repetitive friction against the skin.

Acne vulgaris:  The medical term for common acne, which is characterized by the presence of one or more of the following: blackheads, whiteheads, papules and pustules.

Androgenic: Referring to the hormones that stimulate the sebaceous glands to create sebum.

Androgens: Hormones that stimulate sebaceous glands in addition to other effects on the body. Present in both males and females, androgens are responsible for physical maturation in males and therefore occur in much higher levels in males. Males tend to have more severe acne than females.

Antimicrobial:  Agent, such as a medication, that kills or eliminates microorganisms.

Blackhead: A non-inflammatory acne lesion that is filled with excess oil and dead skin cells. Blackheads are also called “open comedomes” because the surface of the skin remains open.

Chloracne:  Rash characterized by many comedones that develops from exposure to chlorinated chemicals or herbicides.

Closed comedo: A whitehead; a non-inflammatory comedo with white center.

Comedo (plural: comedones): An acne lesion.

Comedogenic: Likely to cause comedones.

Dermatologic surgery: Deals with the diagnosis and treatment of medically necessary and cosmetic conditions of the skin, hair, nails, veins, mucous membranes and adjacent tissues by various surgical, reconstructive, cosmetic and non-surgical methods. This includes laser surgery, cryosurgery, chemical surgery, aspirational surgery and excisional surgery. The purpose of dermatologic surgery is to repair and/or improve the function and cosmetic appearance of skin tissue

Follicle: The tiny shaft in the skin through which a hair grows, and sebum is excreted from sebaceous glands to the surface of the skin.

Hormones: Chemical substances produced by the body that, depending on the hormone, govern many body processes. Certain hormones cause physical maturation during puberty. These are the ones implicated in acne.

Inflammatory: A word that means "causing inflammation." In acne, "inflammatory" is usually used to describe lesions that are inflamed by chemical reactions or bacteria in clogged follicles.

Isotretinoin:  Potent systemic medication used to treat severe forms of acne. Due to potential birth defects, a woman must not take this medication while pregnant or breast feeding and must not become pregnant while taking isotretinoin.

Keloid: Large raised scar that spreads beyond the size of the original wound.

Lipids: Oily substances that include things like fats, oils and waxes. Sebum is made up of lipids. A particular kind of lipid, free fatty acids, are irritating to the skin.

Macule:  A flat spot or patch of skin that is not the same color as the surrounding skin.

Melanin:  Substance that gives hair and skin its color.

Microcomedo: The first stage of comedo formation; a comedo so small that it can be seen only with a microscope.

Nodulocystic acne: A severe form of acne that is characterized by numerous deep, inflamed bumps (nodules) and large, pus-filled lesions that resemble boils (cysts). The nodules tend to be tender when touched and feel firm. The severe inflammation can cause the acne to become very red or even purple. Scarring often results when the acne heals.

Noncomedogenic: Not likely to cause comedones.

Noninflammatory: In acne, comedones that are not associated with redness in the skin.

Open comedo: A blackhead) a noninflammatory comedo with a dark top and firmly packed contents.

Papule: An inflammatory comedo that resembles a small, red bump on the skin.

Papulopustular: A type of acne characterized by the presence of papules and pustules.

Post-inflammatory hyperpigmentation: Excessive skin darkening at places where the skin was inflamed.

Propionibacterium acnes (P. acnes): A normal resident on the skin,
P. acnes will multiply rapidly in clogged hair follicles where sebum is trapped.

Puberty: The time of life when a child begins the physical maturation process toward adulthood. Onset is usually in the early teens and is accompanied by a large increase in hormone production.

Pustule: An inflammatory comedo that resembles a whitehead with a ring of redness around it.

Retinoid: A natural or synthetic substance derived from vitamin A.

Sebaceous glands: Glands in the skin that produce an oily substance called sebum--these glands are the sites of acne lesions. Sebaceous glands are attached to hair follicles and are found mostly on the face, neck, back and chest.

Sebum: The oily substance produced by sebaceous glands.

Steroid acne: Acne that develops from long-term use of corticosteroid medications. Since this condition can develop, corticosteroid medications are prescribed for a limited time.

Systemic therapy: Treatment that consists of taking medication internally, such as in pill form or by injection or infusion.

White blood cells: Components of the blood that help fight off infections.

Whitehead: An acne lesion that forms when oil and skin cells block the opening of a hair follicle. For this reason, whiteheads are called “closed comedomes.”

All content solely developed by the American Academy of Dermatology