Acne refers to the skin disease known as acne vulgaris. The common term for this disease is acne. This skin disease occurs when the pilosebaceous units in the skin go through some changes. These units are basically structures of the skin, and consist of both a hair follicle and the sebaceous gland associated with the hair follicle. When acne is in its sever form, it is inflammatory. But there are also cases when acne also occurs in forms which are not inflammatory. The lesions which occur as a result of acne are known commonly as zits, spots, or pimples.

The most common time during which acne occurs is when people are in their adolescent stage. More than eighty five percent of teenagers are affected by acne. There are also chances that the person will continue to have acne as he moves into adulthood. In most of the cases, acne either gets reduced as time moves on or completely disappears. This usually happens around the time when the individual has reached the early twenties. But it can not be predicted for certain when the acne will disappear totally, and acne can also continue when the individual is in his thirties, forties, and even after that.

The most common areas which are affected by the skin disease known as acne are the upper neck and the face. But even the shoulders, the back, and the chest might get acne. Acne can also occur on the upper arms, but in most of the cases this is not acne but instead it is keratosis pilaris. The usual lesions of acne are inflammatory papules, nodules, comedones, and pustules. Cysts are nodules which are large in size.