What is the term for a hair follicle containing hardened and darkened sebum?

What is the term for a hair follicle containing hardened and darkened sebum?

• A. Comedo
• B. Milia
• C. Pore
• D. Sebaceous cyst

Answer: (A)

A comedo is a hair follicle that becomes clogged with sebum and keratin, forming a plug. When the sebum at the surface is exposed to air, it oxidizes and darkens, producing what clinicians call an open comedo or blackhead. If the plug remains closed, the lesion appears as a white bump, a whitehead. Milia are small keratin-filled cysts, not oil-filled follicles; a sebaceous cyst is a deeper lump from a blocked gland, not the usual clogged follicle described here. The term that fits a hair follicle containing hardened and darkened sebum is a comedo.

A comedo is a hair follicle that becomes clogged with sebum and keratin, forming a plug. When the sebum at the surface is exposed to air, it oxidizes and darkens, producing what clinicians call an open comedo or blackhead. If the plug remains closed, the lesion appears as a white bump, a whitehead. Milia are small keratin-filled cysts, not oil-filled follicles; a sebaceous cyst is a deeper lump from a blocked gland, not the usual clogged follicle described here. The term that fits a hair follicle containing hardened and darkened sebum is a comedo.