Comedo

comedo /com·e·do/ (kom´e-do) pl. comedo´nes   a plug of keratin and sebum within the dilated orifice of a hair follicle, frequently containing the bacteria Propionobacterium acnes, Staphylococcus albus, and Pityrosporon ovale.

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closed comedo  whitehead; a comedo whose opening is not widely dilated, appearing as a small, flesh-colored papule; it may rupture and cause an inflammatory lesion in the dermis.

open comedo  blackhead; a comedo with a widely dilated orifice in which the pigmented impaction is visible at the skin surface.

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com·e·do (km-d)

n. pl. com·e·dos or com·e·do·nes (-dnz)

A blackhead and the primary lesion of acne vulgaris.

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Comedo

A hard plug composed of sebum and dead skin cells. The mildest type of acne.

Mentioned in: Acne

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comedo

pl. comedones; a blackhead; a plug of keratin and sebum within the dilated orifice of a hair follicle frequently containing bacteria. Found in feline and canine acne, hyperadrenocorticism, Schnauzer comedo syndrome (see below).

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Schnauzer comedo syndrome

a condition in which numerous comedones form in the skin over the back of certain predisposed Schnauzer dogs, usually of the miniature variety. The cause is unknown but believed to be an inherited disorder of keratinization.