What is a Pilonidal Sinus?

A pilonidal sinus is a common development associated with a pilonidal abscess. Pilonidal abscesses, also known as pilonidal cysts, are areas of abscess which occur near the sacral area of the spine, often manifesting around the coccyx, between the buttocks. Occasionally, the abscess develops a small sinus tract which drains to the surface of the skin, allowing material from inside the abscess to drain out. This sinus tract is known as a pilonidal sinus.

Young adult males are most likely to develop a pilonidal abscess. The term “pilonidal” means “nest of hair,” reflecting the fact that hair is often found inside the abscess, along with skin debris. It is also not uncommon for opportunistic bacteria to settle in the abscess, causing disease in the patient. Such abscesses are usually very painful, especially because they are located on an area of the body which is subjected to pressure every time someone sits down.

The causes of pilonidal abscesses are not well understood. Some doctors suspect that they originate in ingrown hairs, while others believe that they may be the result of heavy sweating, trauma to the region, or even pressure which might be caused by extended periods of sitting. The pilonidal abscess and accompanying pilonidal sinuses have a long history in the military, especially among drivers who routinely handle rough terrain, suggesting that the dual factors of trauma and pressure can play a significant role.


When this condition develops, a small hole appears above the anus. The hole may drain or leak fluid, including foul smelling fluid which indicates the presence of bacterial infection. Patients usually experience pain or discomfort, as well as soiling of underwear from the leaking fluids.

Treatment for a pilonidal sinus and the underlying abscess can be as simple as applying hot compresses to promote drainage and using antibiotics to encourage the abscess to heal. In some cases, surgery may be recommended to excise the abscess. Surgery is also used if a doctor cannot confirm that the problem is really a pilonidal abscess, as several medical problems such as teratomas can look similar, and it may be better to take the suspicious area of tissue out, just to be safe.

As a general rule, a pilonidal sinus and abscess will not resolve on their own, and treatment is strongly recommended to prevent infection, confirm the diagnosis, and to resolve the associated pain. Many general practitioners or nurse practitioners can provide treatment for a pilonidal cyst, and can refer a patient to a surgeon is surgery is believed to be a better treatment option.


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Will it go away on its own?

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