(1) A closed comedo , or white head, occurs when the blockage is complete.(2) If the plugged follicle, or comedo, stays beneath the skin, it is called a closed comedo or whitehead.(3) If the plug enlarges and is on the surface of the skin, exposed to the air, it is called an open comedo , or blackhead.(4) The basic acne lesion, called the comedo (KOM-e-do), is simply an enlarged and plugged hair follicle.(5) Steroid-induced acne often is of a distinctive variety, being predominantly formed of inflammatory papules and pustules, which are often small and uniformly sized, with few comedones .(6) The first technique works wonders in treating large boils, abscesses (whether hot or cold), and evidently, also big or tight clusters of acne pustules and comedones .(7) This obstruction leads to the formation of comedones , which can become inflamed because of overgrowth of Propionibacterium acnes.(8) In the patient with comedones and inflammatory lesions, a comedolytic agent such as tretinoin, adapalene or azelaic acid may be combined with benzoyl peroxide or a topical antibiotic.(9) If the lipid material accumulates in the hair follicle, we have the formation of comedones , or blackheads.(10) This is a chronic inflammation of the hair follicle and sebaceous gland (pilosebaceous unit) characterized by pustules, comedones , cysts, and scars, and it affects most adolescents.(11) It most often manifests in adolescents as comedones , papulopustules, and nodulocysts.(12) This results in enlargement of the sebaceous glands, which can eventually lead to the development of comedones (black-heads).(13) Retinoids, which are derivatives of vitamin A, function by slowing the desquamation process, thereby decreasing the number of comedones and microcomedones.(14) This subtype resembles acne vulgaris, but with the absence of comedones .(15) Certain occupations and activities seem to favour the formation of comedones or acne.
