(HealthDay News) -- Doctors don't know precisely what causes acne, but experts do know what can make it worse.
The National Institute of Arthritis and Musculoskeletal and Skin Diseases offers this list of examples:
- Hormonal changes related to menstruation.
- Exposure to oil or grease in the work environment.
- Exposure to oil in skin products.
- Pressure on the skin from tightly-fitting helmets or sports equipment.
- Irritants found in the environment, such as high humidity or air pollution levels.
- Picking at or squeezing blemishes on the skin or scrubbing the skin too vigorously.
- Being under emotional stress.