General Surgery Conditions | Pilonidal Sinus

Pilonidal means a 'nest of hairs'


A sinus tract is a small abnormal channel (a narrow tunnel) in the body. A sinus tract typically goes between a focus of infection in deeper tissues to the skin surface. This means that the tract may discharge pus from time to time on to the skin.


A pilonidal sinus is a sinus tract which commonly contains hairs. It occurs under the skin between the buttocks (the natal cleft) a short distance above the anus. The sinus track goes in a vertical direction between the buttocks. Rarely, a pilonidal sinus occurs in other sites of the body.


A pilonidal sinus may not cause any symptoms at first. Some people notice a painless lump at first in the affected area when washing. However, in most cases, symptoms develop at some stage and can be 'acute' or 'chronic'.



Acute (rapid onset) symptoms


Pain and swelling develop over a number of days as an infected abscess develops in and around the sinus. This can become very painful and tender.


Chronic (persistent) symptoms


Around 4 in 10 people have a recurrence of their pilonidal sinus. Usually the sinus discharges some pus. This releases the pressure and so the pain tends to ease off and not become severe. However, the infection never clears completely. This then can mean that the symptoms of pain and discharge can persist long-term, or flare up from time to time, until the sinus is treated by an operation.




If you have an infection then you may be given some antibiotics. Painkillers (such as paracetamol and/or ibuprofen) may be very helpful to improve the pain. It may be that you need to have an emergency operation to incise (puncture) and drain the abscess.


Chronic Symptoms


In most cases, an operation will be advised. There are various operations which are done to cure this problem. There are pros and cons of each operation. The options may include the following:


  • Wide excision and healing by secondary intention. This operation involves cutting out the sinus but also cutting out a wide margin of skin which surrounds the sinus. The wound is not stitched but just left to heal by normal healing processes (healing by 'secondary intention'). This usually means that the wound can take several weeks to heal and requires regular dressing until it heals. The advantage of this method is that all inflamed tissue is removed and the chance of recurrence is low.
  • Excision and primary closure. This means taking out the section of skin which contains the sinus. This is done by cutting the skin either side of the sinus (to form an ellipse shape around the sinus), taking out the sinus, and stitching together the two sides of the ellipse. The advantage for this is, if successful, the wound heals quite quickly. However, the risk of a recurrence, or of developing an infection of the wound after the operation, is higher than the above procedure.
  • In some cases, where the sinus recurs or is extensive, a plastic surgery technique may be advised to remove the sinus and refashion the nearby skin.


There are variations on the above procedures, depending on your circumstances, the size and extent of the sinus, and whether it is a first or recurrent problem.