Acne is caused by an interaction between hormones, skin oils, and bacteria, which results in inflammation of hair follicles (the pores in the skin where hair grows). Acne is characterized by many types of skin abnormalities (lesions).
Acne occurs mainly during puberty, when the sebaceous glands are stimulated by increased hormone levels, especially the androgens (such astestosterone), resulting in excessive sebum production. By a person’s early to mid 20s, hormone levels usually have decreased enough that acne lessens or disappears. However, up to 40% of women may have acne into their 40s.
Other conditions that involve hormonal changes can affect the occurrence of acne as well:
- Pregnancy or menstruation
- Polycystic ovary syndrome
- Certain drugs
- Certain products applied to the skin
- Too-tight clothing
- High humidity and sweating