Cysts are harmless growths in the deeper layers of the skin. They are small closed sacs containing fluid or solid material composed of dead skin cells. There are many types of cysts of different sizes that appear on various parts of the body. Ruptured cysts can become inflamed (red and painful) and discharge pus. Occasionally cysts become infected and resemble a boil. Cysts may require minor surgery to be removed.
Cysts may form when the lining of a hair follicle gets blocked. The cyst sac is filled with a whitish material that can sometimes ooze out onto the skin's surface (most commonly when the cyst is manipulated or traumatized). It is not known why cysts appear or why some people are more prone to get them than others.
If you have a cyst, ask your doctor's advice. Small cysts usually don't need treatment, but can be removed. Larger cysts are usually surgically removed to avoid problems with inflammation and infection, or for cosmetic appearance.
Cysts are treated by making a surgical opening in the skin and removing the sac (excision). This is done under local anesthetic and may require stitches. Cysts may recur and need further treatment. If the cyst is inflamed or infected, antibiotics may be prescribed.