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 
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
Androgenic: Referring to the hormones that stimulate the sebaceous glands to create sebum.
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
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
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 
Closed comedo: A whitehead; a non-inflammatory comedo with white
Comedo
Comedo: (plural: comedones): An acne lesion.
Comedogenic: Likely to cause comedones.
Follicle
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.
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
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
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
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.
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.
Microcomedo: The first stage of comedo formation; a comedo so small that it can be seen only with a microscope.
Nodulocystic acne 
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.
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
Noncomedogenic: Not likely to cause comedones.
Noninflammatory
Noninflammatory: In acne, comedones that are not associated with redness in the skin.
Papule
Papulopustular
Papulopustular: A type of acne characterized by the presence of papules and pustules.
Post-inflammatory hyperpigmentation
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
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
Pustule: An inflammatory comedo that resembles a whitehead with a ring of redness around it.
Retinoid
Retinoid: A natural or synthetic substance derived from vitamin A.
Sebaceous glands
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
Sebum: The oily substance produced by sebaceous glands.
Steroid acne
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
White blood cells: Components of the blood that help fight off infections.
Whitehead
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.”
