A blackhead is a type of acne that occurs when hair follicles become clogged with oil, dead skin cells, and bacteria. Unlike other forms of acne, blackheads have a dark appearance due to oxidation, which occurs when the clogged material is exposed to air. They are commonly found on the face, particularly the nose, but can also appear on the back and shoulders. Blackheads are considered non-inflammatory acne, meaning they do not cause redness or swelling like pimples. They can be treated with over-the-counter products containing ingredients like salicylic acid or benzoyl peroxide. Regular cleansing and exfoliation can also help prevent their formation.