A pilonidal sinus is a small hole, or ‘tunnel’, in the skin, which usually develops at the top of the cleft of the buttocks (where the buttocks separate).
A pilonidal sinus can become infected by bacteria, resulting in pain and swelling. A pus-filled abscess can then develop within the sinus.
Most people associate the word sinus with the nose, but sinuses can occur anywhere in the body. Sinus is simply a medical term that means channel, or cavity.
How common are pilonidal sinuses?
Pilonidal sinuses are uncommon.
Pilonidal sinuses occur most often in men, who account for four out of every five cases. Most cases develop in young adults who are between 18-25 years of age.
Outlook
Once a pilonidal sinus becomes infected, prompt treatment is required to prevent the infection spreading. It is important to prevent the infection from spreading into the blood (sepsis) as this can be serious.
Treatment for a pilonidal sinus involves draining all of the pus out of the abscess. In cases of recurring sinus infection, surgical removal of the sinus is usually recommended.
Continue to next section: Symptoms of pilonidal sinus