Blackheads are another common type of acne that may occur alongside whiteheads or in isolation. With whiteheads, the cause is a clogged pore with closed skin. The cause of blackheads is a clogged hair follicle with open skin. A blackhead appears as a small bump on the skin. The surface tends to be black or dark. Blackheads are one of the more mild types of acne, and while they most commonly form on the face, it's also possible for individuals to develop blackheads on their shoulders, arms, neck, chest, and back. Every hair follicle in the skin is made up of a sebaceous gland and hair. The sebaceous gland secretes oil, which keeps skin soft. When oils and dead skin cells collect in the hair follicle, a bump called a comedone is formed. This is the same bump that causes whiteheads. The difference with blackheads is the bump is exposed to the air, which causes it to take on a dark or black color.
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