What is acne? Acne is a term attributed to plugged pores, commonly known as blackheads and whiteheads, pimples, and even cysts or nodules, occur on the face, neck, chest, back, shoulders and upper arms. Follicles, often called pores, often get blocked with sebum (oil), which normally drains to the surface, and a bacteria propionibacterium acnes, begins to grow. Both whiteheads and blackheads start out as a "microcomedone" which then become skin blemishes called comedones. Acne can be upsetting, disfiguring, sometimes leading to permanent scarring.

There are different types of acne. A white head is a lesion where trapped sebum and bacteria stay below the skin surface. A blackhead, on the other hand, is a lesion where trapped sebum and bacteria partially open to the surface and turn black due to the skin pigment melanin.

A papule is a small solid lesion slightly elevated above the surface of the skin. A pustule, again, is a dome-shaped skin elevation containing pus: a mixture of white blood cells, dead skin cells, and bacteria. It often has a hair in the center. A macule is a temporary red spot left by a healed acne lesion. It is flat and pinkish, with well-defined borders that can persist for days to weeks. A number of macules can contribute to the "inflamed face" appearance of acne. A nodule is a solid dome-shaped or irregularly shaped lesion, characterized by pain, inflammation and extending into deeper layers of the skin. It may cause tissue destruction resulting in scarring.

A cyst is a sac-like lesion containing white blood cells, dead cells, and bacteria. It may be severely inflamed and painful, extending into deeper layers of the skin and can result in scarring.