Three factors contribute to the formation of acne:
- Overproduction of oil (sebum)
- Irregular shedding of dead skin cells resulting in irritation of the hair follicles of your skin
- Buildup of bacteria
These factors can trigger or aggravate an existing case of acne:
- Hormones. Androgens are hormones that increase in boys and girls during puberty and cause the sebaceous glands to enlarge and make more sebum. Hormonal changes related to pregnancy and the use of oral contraceptives can also affect sebum production.
- Certain medications. Drugs containing corticosteroids, androgens or lithium are known to cause acne.
- Diet. Studies indicate that certain dietary factors, including dairy products and carbohydrate-rich foods — such as bread, bagels and chips, which increase blood sugar — may trigger acne.
Acne Risk factors
Hormonal changes in your body can provoke or aggravate acne. Such changes are common in:
- Teenagers
- Women and girls, two to seven days before their periods
- Pregnant women
- People using certain medications, including those containing corticosteroids, androgens or lithium
Other risk factors include:
- Direct skin contact with greasy or oily substances, or to certain cosmetics applied directly to the skin
- A family history of acne — if your parents had acne, you're likely to develop it, too
- Friction or pressure on your skin caused by various items, such as telephones or cellphones, helmets, tight collars and backpacks
- Stress doesn't cause acne, but if you have acne already, stress may make it worse
