Blackheads are caused when hair follicles become clogged with excess oil (sebum) and dead skin cells. Each hair follicle has a sebaceous gland that produces oil to keep the skin soft; however, overproduction of sebum combined with the buildup of dead skin cells can block the follicle opening, creating a bump called a comedo. When this comedo is open to the air, the contents oxidize and turn black, forming a blackhead. Several factors contribute to the formation of blackheads:
- Overproduction of sebum by sebaceous glands
- Accumulation of dead skin cells clogging pores
- Exposure of clogged material to air causing oxidation and black color
- Hormonal changes (puberty, menstruation, certain medications)
- Skin irritation or injury to follicles (e.g., squeezing pimples)
- Stress which can exacerbate acne conditions
Blackheads commonly appear on the face, chest, back, and other areas with a high concentration of oil glands, often where pores are larger or more numerous.
