Acne is the disease of the pilosebaeceous unit (consisting of sebaceous gland connected to hair follicle) that results in plugged pores and outbreak of lesions commonly called as pimples or zits. Acne lesions usually occur on the face, neck back, chest and shoulders where the pilosebaceous units are present in large number. Nearly 17 million people in United States have acne making it the most common skin disease. Acne is not a serious health threat but severe acne can lead to disfiguring, permanent scarring which can be upsetting for the people who suffer from the disorder.
Acne is believed to result from a change in the inner lining of the follicle that prevents the sebum from passing through. For reasons not understood, cells from the lining of the follicle are shed too fast and clump together. The clumped cells plug up the follicles opening so sebum (oil) cannot reach the surface of the skin. The mixture of oil and cells causes bacteria that normally live on the skin, called Propionibacterium Acnes (P.acnes) to grow in the plugged follicles. These bacteria produce chemicals and enzymes that cause inflammation (Inflammation is a characteristic reaction of tissues to disease or injury and is marked by four signs viz. swelling, redness, heat and pain. When the plugged follicle can no longer hold its contents, it bursts and spills everything onto the nearby skin-sebum, shed skin cells and bacteria. Lesions or pimples develop as a result.