Fast Facts: An Easy-to-Read Series of Publications for the Public
Department of Health
and Human Services
Public Health Service
National Institute of Arthritis
and Musculoskeletal and
National Institutes of Health
1 AMS Circle
Bethesda, Maryland 20892–3675
1–877–22–NIAMS (free of charge)
Publication date: March 2005
Revised August 2006
What Is Acne?
Acne is a disease that affects the skin’s oil glands. The small holes in your skin
(pores) connect to oil glands under the skin. These glands make an oily substance
called sebum. The pores connect to the glands by a canal called a follicle. Inside
the follicles, oil carries dead skin cells to the surface of the skin. A thin hair also
grows through the follicle and out to the skin. When the follicle of a skin gland
clogs up, a pimple grows.
Most pimples are found on the face, neck, back, chest, and shoulders. Acne is not
a serious health threat but, it can cause scars.
How Does Acne Develop?
Sometimes, the hair, sebum, and skin cells clump together into a plug. The
bacteria in the plug causes swelling. Then when the plug starts to break down, a
There are many types of pimples. The most common types are:
l Whiteheads. These are pimples that stay under the surface of the skin.
l Blackheads. These pimples rise to the skin’s surface and look black. The black
color is not from dirt.
l Papules. These are small pink bumps that can be tender.
l Pustules. These pimples are red at the bottom and have pus on top.
l Nodules. These are large, painful, solid pimples that are deep in the skin.
l Cysts. These deep, painful, pus-filled pimples can cause scars.
Who Gets Acne?
Acne is the most common skin disease. People of all races and ages get acne. But
it is most common in teenagers and young adults. An estimated 80 percent of all
people between the ages of 11 and 30 have acne outbreaks at some point. Some