Blackheads, also known as open comedones, occur when hair follicles become clogged with a combination of dead skin cells and excess oil (sebum). The dark coloration is due to the oxidation of the oil as it is exposed to air. Factors like hormonal changes, certain medications, improper skincare routines, and genetics can contribute to the development of blackheads. Proper cleansing, exfoliation, and using non-comedogenic products can help prevent and manage blackheads.