Blackheads are a type of comedo. Comedones occur when the pores in the skin become plugged with dead skin cells and an oily, protective substance known as sebum.
Blackheads don’t mean your skin is dirty. Melanin, which is what gives skin its color, is found in sebum, too. When that melanin is exposed to air (what’s called oxidation) it turns dark, and that’s what gives blackheads their typical color. So resist the impulse to scrub your skin hard to remove the “dirt,” since that’s not what’s causing
pimples, plus scrubbing can irritate skin and make acne even worse.
Blackheads are also called “open comedones.” If you’re decided to talk to a dermatologist she may refer to blackheads by another name: a comedone. This is a small, flesh-colored, white, or dark bump that reaches the surface of the skin (they’re what make your skin feel rough and sandpaper-y). Blackheads are called “open comedones” because the bump has surfaced; by comparison, a whitehead is a “closed comedone” because it’s beneath the skin. Both are what’s called “non-inflammatory acne,” whereas papules and pustules (those bigger, painful zits) are considered “inflammatory acne.”