Blocked Skin Pores – Oil from the sebaceous glands fills up the pores to keep the skin hydrated. Skin cells (shed from the lining of the pore) bunch together. Acne occurs when the bunched skin cells block the pore and the oil cannot escape.

Bacteria – Good bacteria are a normal part of the skin’s surface. It keeps skin from being attacked by harmful bacteria. When oil is trapped in the pores, the normal skin bacteria will grow inside the blocked pore. Bacterium produces chemicals that change the oil, which make it more irritating to the skin and causes inflammation.

Inflammation – Inflammation (or swelling and redness) of the skin occurs because the body’s immune system is fighting off a foreign substance. In the case of acne, this foreign substance is bacteria that becomes trapped in the pore.