Hormones and genetics have a role in the development of acne. However, other factors may make symptoms worse.

These include:

• Oil-based personal care products such as make-up, sunscreens or hair care products
• Stress
• Squeezing or picking blemishes
• Using harsh, abrasive scrubs or cleansers that irritate the skin
• Certain medicines, such as those containing particular steroids, hormones or lithium, as well as some anti-epileptic medication
• Friction or pressure caused by helmets, tight collars, backpack straps, etc
• Pollution and high humidity
• Smoking.