Acne vulgaris can run in families suggesting that there is a genetic component. The exact genes that relate to acne are still largely unknown.
Most acne is triggered by normal hormonal changes during adolescence. In females with irregular and abnormal periods, polycystic ovarian syndrome may be an underlying factor. Use of anabolic steroids can induce severe scarring
acne. Sometimes severe stress can cause hormonal changes which can worsen acne.
A high glycaemic index (GI) diet can sometimes worsen acne. There is mounting evidence that skim or skinny milk and chocolate can also worsen acne in some individuals (but is not the cause of acne). Whey protein supplements can flare acne.
Thick cosmetic make-up (concealers) and sometimes hair products such as hair wax, (which can run off on the face), can also cause or worsen acne.