Clogging of hair follicles with dead skin cells and oil causes acne, a skin condition. It is a chronic, inflammatory skin condition due to which pimples and spots are formed on the face, shoulders, neck, chest, back and upper arms.

Acne is most common among teenagers, but it may affect people of any age. This condition occurs commonly during puberty, during which the sebaceous glands activate. A major population experiences acne between the ages of 12 and 24.

A single factor is not responsible for causing acne. Acne occurs when the sebaceous (oil) glands that are attached to hair follicles get stimulated. This happens at the time of puberty. Hormonal changes may also cause acne. Some of the major causes are: hair follicles getting clogged by dead skin cells and oil; excessive oil production; excessive activity of any type of hormone; and bacteria.

Acne appears usually on the face, forehead, shoulders, upper back, chest and upper arms. Acne is a disease in which oil glands are involved at the base of hair follicles. Most often, acne is found to occur on the face on the following areas: cheeks; chin; forehead or nose; jawline; ears or earlobes; and hairline and scalp.

Several changes occur on the skin due to acne. With the onset of puberty, the facial skin started changing. Various receptors causes human skin to respond to various signals such as hormonal. The sebaceous glands produce an oily substance, more during puberty when it leads to oily skin.