The word pilonidal means a nest of hairs and a sinus tract is an abnormal narrow channel or cavity in your body. Pilonidal sinuses are infected tracts beneath your skin that predominantly occur at the end of your tailbone, an area called the natal cleft where the buttocks separate.
Although less common, a pilonidal sinus can also occur between your fingers and in your belly button and may present with more than one channel or sinus tract.
The exact cause of pilonidal sinus is unknown. It is believed that ingrown hairs combined with changing hormones (pilonidal sinuses occur after puberty), friction (sitting for a long time or from clothing) and infection (ingrown hair and friction can irritate the skin and cause inflammation leading to bacterial invasion) contribute to pilonidal sinus.
A pilonidal sinus is found more commonly in young adults and occurs most often in men as they have more body hair than women. Having a sedentary job which requires a lot of sitting, obesity, having a deep hairy natal cleft, or a family history of pilonidal sinuses can make you more prone to this condition.
A pilonidal sinus may not have any symptoms at first or can start off as a small painless lump. Once it is infected it becomes inflamed, fills with pus and develops into a painful cyst.
Over a few days you may experience symptoms like:
The symptoms can be rather quick in onset once infection occurs. Pain can be severe and may be experienced whether sitting or standing. Pain can affect your ability to perform your daily activities and can worsen without treatment. Discharge of pus usually releases the pressure and eases the pain, but if the infection is not treated it can lead to recurrence of the pilonidal sinus.
If you experience the above symptoms you should see your doctor right away to make a diagnosis and prevent further worsening of your condition.
When you present with symptoms of a pilonidal sinus, your doctor will perform a detailed physical examination. You will be asked for your medical history, which would include information regarding any drainage or change in appearance of the affected area. Your doctor will perform a visual examination to look for tenderness, redness, swelling and inflammation around the affected area. Your doctor may also order a blood test to check for increased white blood cells which may be an indication of an infection. In rare cases your doctor will recommend a CT scan to confirm your condition.
Your doctor may conduct tests to rule out other conditions such as a dermoid cyst (tumor of the germ cell) that can resemble a pilonidal cyst.
Treatment may not be necessary if your pilonidal sinus does not become infected. The area can be kept clean and dry and the surrounding hair removed by shaving or with hair removal creams. However, infected pilonidal sinuses are treated with surgery. Your doctor may perform any of the following procedures:
Incision and Drainage: This procedure involves cutting open the sinus tract and draining the pus from the abscess. This is a minor procedure and is usually performed under general anesthesia. You will be able to return home either on the same day of the procedure or the day after. A dressing will be applied and you will have to visit wound care or have home health daily for dressing changes.
For recurrent infections of your pilonidal sinus, you may be recommended to undergo surgery to remove the sinus and prevent further infections with any of the following procedures: