Pilonidal disease is a chronic infection of the skin in the region of the buttock crease (Figure 1).
The condition results from a reaction to hairs embedded in the skin, commonly occurring in the cleft
between the buttocks. The disease is more common in men than women and frequently occurs between
puberty and age 40. It is also common in obese people and those with thick, stiff body hair.
Symptoms vary from a small dimple to a large painful mass. Often the area will drain fluid that
may be clear, cloudy or bloody. With infection, the area becomes red, tender, and the drainage (pus)
will have a foul odor. The infection may also cause fever, malaise, or nausea.
There are several common patterns of this disease. Nearly all patients have an episode of an
acute abscess (the area is swollen, tender, and may drain pus). After the abscess resolves, either
by itself or with medical assistance, many patients develop a pilonidal sinus. The sinus is a
cavity below the skin surface that connects to the surface with one or more small openings or
tracts. Although a few of these sinus tracts may resolve without therapy, most patients need a
small operation to eliminate them.
A small number of patients develop recurrent infections and inflammation of these sinus tracts.
The chronic disease causes episodes of swelling, pain, and drainage. Surgery is almost always
required to resolve this condition.
The treatment depends on the disease pattern. An acute abscess is managed with an incision and
drained to release the pus, and reduce the inflammation and pain. This procedure usually can
be performed in the office with local anesthesia. A chronic sinus usually will need to be excised
or surgically opened.
Complex or recurrent disease must be treated surgically. Procedures vary from unroofing the
sinuses to excision (Figure 2) and possible closure with flaps. Larger operations require longer
healing times. If the wound is left open, it will require dressing or packing to keep it clean.
Although it may take several weeks to heal, the success rate with open wounds is higher. Closure
with flaps is a bigger operation that has a higher chance of infection; however, it may be
required in some patients. Your surgeon will discuss these options with you and help you select
the appropriate operation.
If the wound can be closed, it will need to be kept clean and dry until the skin is completely
healed. If the wound must be left open, dressings or packing will be needed to help remove secretions
and to allow the wound to heal from the bottom up.
After healing, the skin in the buttocks crease must be kept clean and free of hair. This is
accomplished by shaving or using a hair removal agent every two or three weeks until age 30.
After age 30, the hair shaft thins, becomes softer and the buttock cleft becomes less deep.