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Pilonidal Sinus

What is a pilonidal sinus?

The word 'pilonidal' is a combination of the Latin words for 'hair' (pilus) and 'nest' (nidus). A pilonidal sinus is a cavity just under the skin that forms near or on the upper crease of the buttocks - centrally on the lower back just where the buttocks start to form a 'cleft'.

What causes a pilonidal sinus?

As the derivation of the word 'pilonidal' implies, the sinus - cavity - forms when hair on the lower back grows into and underneath the skin. Because this hair has been exposed to the air it may take bacteria with it under the skin and cause infection.

What are the symptoms of a pilonidal sinus?

Any bacterial infection under the skin may cause:

  • Pain.
  • Swelling.
  • Discharge of blood.
  • Discharge of pus.

The condition primarily affects young adults (in their teens and twenties) and can affect men and women. Where this is an ongoing problem it is referred to as 'pilonidal disease'.

How is a pilonidal sinus treated?

A pilonidal sinus can be treated without surgery, however where the condition recurs, or where the infection or the symptoms are severe, surgery is often recommended.