Definition Sebaceous cysts are sacs just beneath the skin that are filled with an oily, white, semisolid material. If the material becomes infected, the cyst will be red and painful. Sebaceous cysts are commonly seen on the scalp, labia, scrotum, chest, and back, but can be found anywhere on the body.
What is going on in the body? The material produced by oil glands is called sebum. When oil glands become plugged or clogged, the sebum is unable to escape from the gland. The sebum collects and the gland enlarges, forming a sebaceous cyst. The material within a sebaceous cyst is very oily and somewhat white. It can easily become infected.
What are the signs and symptoms of the condition? Symptoms of a sebaceous cyst include a 1 to 5-cm lump or swelling that is dome-shaped and has a smooth surface. The cyst is usually white or the same colour as the skin. These cysts can become irritated by clothes rubbing on them or by shaving. They may become bright red, swollen, and painful if infected.
What are the causes and risks of the condition? There is no known cause for sebaceous cysts. Some people do seem to be prone to them. The source may be a malformed hair follicle or clogged sebaceous gland. Injury or hormones may increase the size of the cyst. This disorder does not seem to be genetic or contagious.
What can be done to prevent the condition? There is no known way to prevent sebaceous cysts. Good personal hygiene has been recommended, has not been proven to prevent cysts.
How is the condition diagnosed? The diagnosis of a sebaceous cyst is based on examination. The cyst is compared to the person's normal sebaceous glands.
What are the long-term effects of the condition? In most people, sebaceous cysts are benign and cause no problems. But in some people, the cysts can become infected or rupture, causing swelling and pain.
What are the risks to others? Sebaceous cysts are not contagious.
What are the treatments for the condition? In most cases, no treatment is needed for sebaceous cysts. The cysts are usually small and are not bothersome at all. Sometimes the location makes them annoying because they rub against clothing. They may be unsightly or become infected. In these cases they may need to be removed.
If an abscess develops, antibiotics are often given. When cysts and abscesses are removed, both the sac and the material inside are taken. This helps prevent a recurrence. Sebaceous cysts may disappear on their own. Or they may remain in the same place and the same size without causing any problems.
What are the side effects of the treatments? Antibiotics can cause stomach upset or allergic reactions. Surgical drainage poses the risk of pain, infection, bleeding, or allergic reaction to anaesthesia.
What happens after treatment for the condition? There are few complications from sebaceous cysts. If left untreated, a cyst can become an abscess as the result of infection. Recurrence of these cysts is common, even when the sac has been removed. If even a small portion of the sac is left, the cyst can recur.
How is the condition monitored? Sebaceous cysts can be monitored by watching the size and noting any redness or swelling that may indicate infection. Any new or worsening symptoms should be reported to the doctor.
Author: James Broomfield, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
