Pilonidal cyst (pilonidal sinus): symptoms, treatment and recurrence

The NHS says treatment is not needed if there are no signs of infection; a watch-and-wait approach is recommended. For an infected pilonidal sinus, treatment depends on your symptoms, the size of the sinus and whether it is the first infection or keeps coming back. You will usually be offered painkillers such as paracetamol and NSAIDs to reduce pain and swelling.

A painful, swollen abscess usually needs to be cut and the pus drained, and you may need antibiotics. If the sinus keeps coming back and is painful, bleeding or leaking, your doctor will discuss several options.

The NHS says most people with a pilonidal sinus do not notice it unless it becomes infected. An infection causes pain and swelling at the top of the cleft of the buttocks, and a pus-filled skin abscess can develop, sometimes suddenly, making it difficult to sit down.

If you keep getting infections you may have ongoing problems, such as discomfort or pain and pus or blood regularly seeping out. A hospital leaflet describes acute symptoms as increasing pain and swelling over a number of days, and chronic symptoms as less intense pain with a discharge of pus that comes and goes.

Some people notice a painless lump when washing, according to the same leaflet.

The NHS says to ask for an urgent GP appointment or contact NHS 111 if you have a small lump at the top of your bottom that is painful, bleeding or leaking pus. These symptoms can develop quickly, often over a few days, and are signs of infection that need to be treated.

After an operation, a hospital leaflet advises seeing your GP if the wound is swollen and hot, red and painful, or if you have a high temperature or feel feverish.

The NHS says it is not clear what causes a pilonidal sinus. A skin problem, pressure or friction may cause hair between the buttocks to be pushed inwards. This may be hair growing around the buttock area or loose hair shed from the buttocks or elsewhere that gathers around the cleft and enters the sinus.

Pilonidal sinuses are more common in men because they tend to be hairier, and sitting for long periods can increase your chances. A hospital leaflet adds that factors that raise risk include obesity, a sedentary occupation, family history and previous persistent irritation or injury to the area, and says it is rare in children and in people over 40.

The NHS says that if the sinus is not infected, it is very important to keep the area between the buttocks clean by showering or bathing regularly, and not to shave the area unless a GP advises you to.

After an operation the NHS advises keeping the area clean, wearing comfortable loose-fitting cotton underwear, eating plenty of fibre to avoid straining, and not lifting heavy objects or doing strenuous exercise for the first week or so. It says not to ride a bike for 6 to 8 weeks and not to go swimming until the wound has completely healed. A hospital leaflet adds that you should wash with plain water and a soft cloth, dry gently, avoid soap and talc and avoid constipation.

The NHS says most people are able to return to work within 2 weeks of surgery, depending on the procedure, how quickly you recover and the type of job. You may have a follow-up appointment with your specialist, usually about 6 weeks later.

Healing time depends on the technique. A hospital leaflet says a wound left open after wide excision can take several weeks to months to heal and needs regular dressing, which the NHS says gives the lowest risk of recurrence, while closure heals more quickly but with a higher risk of infection or recurrence.

A hospital leaflet says that most cases occur in young adults or teenagers and that it is rare in children. A teenager with a painful lump at the top of the buttock cleft should be seen by a GP, who can treat infection or refer on if it keeps coming back.

The sources used here do not give specific guidance on pilonidal sinus in pregnancy. If you are pregnant and develop a painful swelling in this area, see a GP or midwife promptly so that infection is treated safely.

On the NHS, an infected sinus is usually seen by a GP or urgent care centre, with drainage of an abscess on the same day where possible, and referral to a surgical team for recurrent problems. Day-case surgery is usual.

Private surgeons also offer excision and endoscopic treatments. Whichever route you choose, ask which technique is proposed, the chance of recurrence, how long the wound will take to heal, and who will arrange the dressings and follow-up.