Sebaceous filament
A sebaceous filament is a tiny collection of sebum and dead skin cells around a hair follicle, which usually takes the form of a small, yellow to off-white hair-like strand when expressed from the skin. These filaments are naturally occurring, and are especially prominent on the nose. They are commonly mistaken for blackheads. In 1979, David A. Whiting described them in a review in the Western Journal of Medicine as "a loose, porous mass of horned detritus".Anatomy and physiology
Human skin contains sebaceous glands, which secrete an oily substance known as sebum into hair follicles. Sebum travels to the surface of the skin, where it lubricates skin and hair. Hair follicles can become plugged in visible comedones, but sebaceous filaments are visible build-ups of sebum in healthy follicles.Appearance and characteristics
Sebaceous filaments and blackheads are often confused, but they are not the same thing. While sebaceous filaments are a natural component of pore anatomy, blackheads are considered to be acne. They are caused by the pore becoming clogged with bacteria, dead skin, and sebum. They appear on the skin as black, raised bumps, and can vary in size. After a blackhead heals, it may not come back. Sebaceous filaments do not disappear since they are a natural part of the skin and required to bring sebum to the skin surface.