A pilonidal sinus is an infected tract under the skin between the buttocks. This is a common condition often seen in hairy men and women. Treatment usually involves an operation.
What is a pilonidal sinus?
- Pilonidal means ‘nest of hairs’.
- A sinus tract is a narrow abnormal tunnel in the body.
A pilonidal sinus is a sinus tract (abnormal tunnel) which commonly contains hairs. It occurs under the skin between the buttocks (the natal cleft) a short distance above the back passage (anus). The sinus track goes in a vertical direction between the buttocks. It is important to note that a pilonidal sinus can occur in other sites of the body.
What causes a pilonidal sinus?
The exact cause is not clear. Some theories include a small congenital minor abnormality in the skin between the buttocks. This may partly explain why the condition may run in some families. Part of the abnormality in this part of the skin may be that the hairs grow into the skin rather than outwards. Another theory is that you develop skin dimples (skin pits) in the skin between the buttocks. These may develop as a result of local pressure or friction causing damage to the small structures below the skin which are responsible for making hairs (the hair follicles). Because of local pressure, growing hair in the natal cleft may get pushed into the skin pits.
The hair fragments when become ‘stuck’ in the skin cause irritation and associated inflammation. Inflamed skin quickly becomes red, inflamed & infected and so a recurring or persistent infection tends to develop in the area. The infection causes the sinus to develop which often contains broken pieces of hair and a foul smelling discharge.
(A similar condition can occur between the fingers of hairdressers caused by customers’ hair entering moist, damaged skin.)
Who gets pilonidal sinus?
Anybody can get a pilonidal sinus as we all have hairs. It is four times more common in men (as they are likely to be hairier than women).
Risk factors include:
- A job involving a lot of sitting (a sedentary occupation)
- Being overweight (obesity)
- A previous persistent irritation or injury to the affected area
- Having a hairy, deep natal cleft
- A family history of the condition
symptoms of pilonidal sinus:
A pilonidal sinus may be asymptomatic. You may not be aware that you have one. Some people notice a painless lump at first in the affected area when washing. However, in most cases, problems develop at some stage and can be ‘acute’ or ‘chronic’.
Sudden (Acute) symptoms
You may develop increasing pain and swelling over a number of days as a ball of pus with surrounding skin infection (an infected abscess) develops in and around the sinus. This can become very painful and tender. Sometimes these can spontaneously burst releasing foul smelling pus which may contain some tufts of hair.
Persistent (chronic) symptoms
You may have some pain which is less intense than the acute symptoms. 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 can mean that the symptoms of pain and discharge can last long-term, or flare up from time to time, until the sinus is treated by an operation.
How do you treat a pilonidal sinus?
If you have no symptoms
If you have no symptoms then you will normally be advised to clear the affected area of hairs (by shaving, etc) and to keep the area clean with good personal hygiene. By doing this you are likely to keep the infection away, but by no means a permanent solution for the problem.
Sudden (acute) symptoms
If you have an infection then you may be given some medicines called Antibiotics. Please ensure that the antibiotics are taken as per your physician advise. Painkillers (such as paracetamol and/or ibuprofen) are helpful to improve the pain. It is likely more often than not that you will need an operation to puncture (incise) and drain thepus with surrounding skin infection (abscess). This is usually done in hospital, likely under some sort of anaesthesia.
If you have persistent symptoms & Problems
Usually your doctor will suggest surgery. There are variety of operations which are done to get rid of this problem. Your surgeon will be able to give the details and the pros and cons of each operation. Some of the surgical options include :
Wide excision and healing by secondary intention( leaving the wound open).
This operation involves excision of the sinus along with some margin of skin which surrounds the sinus. The wound is not closed but just left open to heal by natural healing processes (healing by ‘secondary intention’). This usually requires several weeks of regular dressing changes until it heals fully. The advantage of this method is that all inflamed tissue is removed and the chance of the condition coming back (recurrence) is low. Please do note that the wound healing is likely to take often more than 4-6 weeks.
Excision and primary closure.
This means taking out the section of skin which contains the sinus. This is done by cutting out an oval-shaped (ellipse) flap of skin either side of the sinus, which takes out the sinus, and stitching together the two sides of the ellipse. The advantage for this is, if successful, the wound heals quite quickly. The risk of a recurrence or of developing a wound infection after the operation is higher than the above procedure. This risk may be reduced by using a wound technique in which the line of stitches was moved away from between the buttocks.
Sometimes these pilonidal sinuses can be extensive and a plastic surgeon will be involved. They have numerous ways of tackling the problem which often may involve skin flaps and other plastic surgical techniques.