Acne is an inflammatory disease that directly involves the sebaceous glands of the skin and is characterised by papules, pustules or comedones. Acne normally occurs in the areas of the skin that contains the largest number of oil glands, specifically the face, chest, shoulders and back.

Acne is the overproduction of oil (sebum) by the oil glands of the skin. Sebum (oil) normally drains to the surface, but in cases of acne, the sebum(oil) and dead skin cells become trapped within the hair follicle, creating a plug within the pore, this plug is called a comedo. There are two types of acne, non-inflammatory and inflammatory acne.

Examples of non-inflammatory comedos are whiteheads and blackheads. Whiteheads are caused by trapped sebum and bacteria that stays below the skin surface. Whiteheads may show up as small white dots or bumps and can sometimes be so small that it is invisible to the naked eye. Blackheads are an accumulated mixture of oil, bacteria and dead skin cells in blocked skin pores which are open to the surface, allowing the melanin in the trapped sebum to oxidise and become black. Blackheads cannot be washed away as it isn't dirt. Blackheads can take a long time to disappear as the contents of the blackhead drains to the surface very slowly.

Inflammatory acne varies in severity depending on the damage to the follicle wall and amount of infection present. Examples of inflammatory acne are papules and pustules. A papule occurs when there is a break in the follicular wall, white blood cells rush in and the pore becomes inflamed, a pustule forms several days later when the blood cells make their way to the surface of the skin. People usually refer to this as a zit or pimple. An inflamed lesion can sometimes completely collapse or explode, severely inflaming the surrounding skin and even engulfing the neighbouring follicles. These lesions are called nodules or cysts. A nodule is when a follicle breaks along the bottom and total collapse can occur, this causes a large inflamed bump than can be very sore. Pus filled lesions can occur as a result of a severe inflammatory reaction.

Acne mostly affects teens and preteens, it occurs when there is a surge of the androgen hormone (male hormones) within the body, this is why teen boys normally suffer with acne longer than girls do. Androgens stimulate the sebaceous glands, creating an oilier complexion. Any hormonal change in your body can cause acne, examples are: puberty, menstruation, pregnancy and menopause.