Comedo

A comedo (plural: comedones) is a skin lesion that is a primary sign of acne. It is essentially a hair follicle that has become clogged with sebum (oil) and dead skin cells. Comedones can be open (blackheads) or closed (whiteheads).

Types:

• Open Comedo (Blackhead): This type of comedo has a wide opening to the skin's surface. The dark color is not due to dirt, but rather to the oxidation of melanin (skin pigment) and sebum upon exposure to air.

• Closed Comedo (Whitehead): This type of comedo has a very small or closed opening to the skin's surface. The sebum and dead skin cells remain trapped beneath the skin, resulting in a small, white or flesh-colored bump.

Formation:

Comedones form when the normal shedding of dead skin cells is disrupted, causing them to mix with sebum and clog the hair follicle. Increased sebum production, often influenced by hormones (especially during puberty), can also contribute to comedo formation. Bacteria, particularly Cutibacterium acnes (formerly Propionibacterium acnes), can thrive within the blocked follicle, leading to inflammation and the development of more severe acne lesions.

Treatment:

Treatment for comedones typically involves over-the-counter or prescription topical medications containing ingredients like salicylic acid, benzoyl peroxide, or retinoids. These ingredients help to exfoliate the skin, unclog pores, and reduce sebum production. In some cases, manual extraction by a dermatologist or esthetician may be necessary, especially for stubborn or deep-seated comedones. Good skincare practices, including regular cleansing and gentle exfoliation, can also help to prevent comedo formation.