comed

A comed, or comedo (plural comedones), is a clogged hair follicle in the skin composed mainly of keratin and sebum. Comedones are a central feature of acne vulgaris but can occur in other conditions as well. They are classified as open or closed: an open comedone, commonly called a blackhead, has a dilated follicular opening with exposed sebum that darkens on exposure to air; a closed comedone, or whitehead, remains a plug beneath an intact pore and appears as a small, flesh-colored bump.

Pathophysiology involves follicular occlusion from abnormal keratinization, increased sebum production (often influenced by androgens), and bacterial activity within the follicle. Propionibacterium acnes (Cutibacterium acnes) colonization can contribute to inflammation around comedones, particularly in acne vulgaris. Comedones themselves are noninflammatory lesions, while inflammatory acne includes papules, pustules, and nodules.

Clinically, comedones are most common on the face but can appear on the chest, back, and shoulders. They are typically non-tender and may be accompanied by other acne lesions. Diagnosis is usually clinical, based on appearance and distribution.

Management focuses on preventing clogged follicles and promoting desquamation. Topical retinoids (such as adapalene or tretinoin) help normalize follicular turnover, while benzoyl peroxide reduces bacterial load. Salicylic acid aids in pore clearance. In some cases, professional extraction of comedones is performed. For more extensive acne, systemic options (antibiotics or isotretinoin) may be considered under medical supervision. Regular cleansing with noncomedogenic products and avoiding picking or squeezing can help prevent scarring.