Pilonidal (say "py-luh-NY-dul") disease is a chronic skin infection in the crease between the buttocks. People with this condition have one or more cysts in that area that tend to get inflamed and infected. A pilonidal cyst may look like a small dimple (called a "pit" or "sinus"). Hair may stick out from it.
Experts think pilonidal cysts may form in one of three ways:
A hair follicle in the skin becomes irritated or stretched. This may be caused by exercise that affects the buttocks area (such as horseback riding or cycling), tight clothing around the buttocks, heat, or heavy sweating. The hair follicle may become blocked and infected and then open into the surrounding tissue, forming an abscess. Continued exercise or walking often pulls hair into the abscess.
A loose hair may get trapped in the crease between the buttocks. This is more common with coarse or stiff hair. The hair can poke into the skin, especially if there is already an irritated hair follicle. Walking and exercise can pull the hair farther into the skin. A cyst then forms around the hair and can become infected.
Some cysts may be present at birth (congenital).
What are the symptoms?
Pilonidal disease often has no symptoms. If a cyst gets infected (called an abscess), you may have:
Redness or swelling.
Pus or blood draining from the abscess.
Pain when you walk or sit.
How is pilonidal disease diagnosed?
A physical exam of the buttocks is usually all doctors need to diagnose pilonidal disease. You probably won't need any other tests unless the area doesn't heal or your doctor thinks there may be another problem.
How it is treated?
If the cyst gets infected or is a problem, your doctor may need to open and drain the cyst. This procedure can be done in your doctor's office. You may get antibiotics if the infection is severe. The cyst may take a month or more to heal.
You may need to have surgery (excision) to remove the cyst. Surgery may need to be done if:
It gets infected again.
It doesn't heal after being drained.
Your cyst has more than one opening.
Surgery may be done at an outpatient surgical center or hospital. It may take 6 weeks or longer to heal.
Cysts can come back after being drained. Surgery works better as a permanent cure.
What can you do at home for a pilonidal cyst?
While you are being treated for an infected cyst:
Keep the area dry and clean. Your doctor may want you to use soap or an alcohol swab to clean the area.
Soak in a warm tub several times a day.
Take nonprescription pain medicine if needed.
For cysts that are not causing symptoms or after you have had surgery to remove a cyst:
Keep the area dry and clean.
Try not to sit on hard surfaces for long periods of time.
Keeping the area free of hair may also help. Talk with your doctor about what he or she recommends.
Marcello PW (2010). Diseases of the anorectum. In M Feldman et al., eds., Sleisenger and Fordtran's Gastrointestinal and Liver Disease, 9th ed., vol. 2, pp. 2257-2274. Philadelphia: Saunders.
ByHealthwise Staff Primary Medical ReviewerAnne C. Poinier, MD - Internal Medicine Adam Husney, MD - Family Medicine E. Gregory Thompson, MD - Internal Medicine Specialist Medical ReviewerMartin J. Gabica, MD - Family Medicine