Acne vulgaris is a form of acne that affects people all over the world. It is mainly found in teens, but adult cases are quite common. The exact cause of the condition is unknown.

All cases begin with a comedone, or acne lesion, that is clogged with oil and bacteria. It lies beneath the skin and grows as the skin produces oil (sebum). The bacteria feed off the oil and it can become enlarged and swollen. If this occurs, the skin in turn becomes irritated as white blood cells try to fight the inflammation.

If the clogged follicle stays beneath the surface of the skin, but does not become inflamed, it is called a whitehead, or closed comedone. If the plug enlarges and pushes through the skin