This bumpy skin can sometimes be sore. Acne usually develops on the face, but can also be found all over the body, especially the neck, chest, back and arms. People who are prone to acne generally have good skin that is out of balance. They also tend to have skin that is never totally clear of acne. Skin prone to acne usually has a greasy touch to it by midday.
Active acne is the presence of more that ten acne lesions at any given time.
Blackheads on the nose and chin, as well as cysts and pustules are common. Sebaceous glands become overactive due to internal factors such as a surge in hormones. Puberty is often the cause of a hormonal surge. Surges can also be cyclical, preceding menses. Sebaceous glands can be overstimulated by stress.