Acne is a problem caused by too much oil being secreted on to the skin by the glands at the base of the hair follicles. The function of the oil is to keep the skin healthy and lubricated but when too much is present the pores can get blocked and this causes a bacterial infection. The normal cause of the excess secretion of oil tends to be hormonal imbalances usually during puberty and often during menstrual periods and possibly pregnancy for females. There are additional causes such as stress and medications which can also have an effect.