Health Insights · Minor injuries & skin
Pilonidal sinus: managing a common but troublesome problem
A pilonidal sinus is a small tunnel in the skin at the top of the buttock cleft, caused by hairs working their way into the skin and provoking inflammation. It affects young adults, more often men, and it ranges from a painless dimple noticed by accident to a recurrent abscess that disrupts work and study.
Seek same-day assessment if there is
- a rapidly enlarging, exquisitely painful swelling
- fever, shivering or feeling generally unwell
- spreading redness across the buttock or lower back
- severe pain out of proportion with rapid deterioration
- these symptoms with diabetes or a weakened immune system
An abscess needs draining, and antibiotics alone will not resolve it. Rapidly spreading infection in this area is uncommon but serious. In an emergency call 999, or go to the Royal London Hospital Emergency Department, Whitechapel Road, London E1 1FR.
How it presents
- one or more small pits or dimples in the midline at the top of the buttock cleft
- intermittent discharge — blood, pus or clear fluid — staining underwear
- a painful swelling when it becomes infected, often coming on over a day or two
- pain on sitting, driving or cycling
- sometimes nothing at all until the first abscess
Why it happens
Hairs — usually from the back or head rather than growing there — are driven into the skin of the cleft by friction and movement. The body treats them as foreign material and forms an inflammatory tunnel around them. It is commoner in people with coarse dark body hair, those who sit for long periods (drivers, students, office workers), and after a period of weight gain. It is not caused by poor washing, though hygiene helps once it exists.
If it becomes an abscess
- Incision and drainage under local anaesthetic gives immediate relief. This is the treatment; antibiotics are added only where there is surrounding cellulitis or you are systemically unwell.
- The cavity is packed or left open and takes two to six weeks to heal.
- Around half of people go on to develop a chronic sinus needing definitive treatment.
- Daily showering and gentle irrigation of the wound speeds healing.
Definitive surgery
There is no single best operation, and the choice trades healing time against recurrence risk. This is worth discussing properly rather than accepting the first option offered.
- Pit picking (Bascom or Gips procedure) — minimally invasive, removes the pits and cleans out the cavity through small incisions. Quick recovery, back to work in days, moderate recurrence rate, and repeatable.
- Excision left open to heal — low recurrence, but healing takes six to twelve weeks with daily dressings.
- Excision with flap closure (Karydakis or Limberg) — flattens the cleft and moves the scar off the midline. Lowest recurrence for extensive disease, larger operation, two to four weeks off.
- Midline closure is now generally avoided; recurrence is high because the scar sits in the cleft where the problem started.
- Endoscopic and laser techniques are available in some centres.
Reducing recurrence
Helps
- Hair removal from the cleft — laser has the best evidence and outlasts shaving
- Keeping the area clean and thoroughly dry
- Losing excess weight, which reduces the depth of the cleft
- Breaking up long periods of sitting; a cushion for drivers
- Loose cotton underwear
Avoid
- Shaving with a razor, which produces sharp stubble that penetrates skin more easily
- Waiting for a third or fourth abscess before seeking definitive treatment
- Assuming antibiotics will resolve an abscess
- Prolonged cycling or driving during a flare
- Picking at the pits
Why come to us. An acute pilonidal abscess is intensely painful and sitting on an NHS list for days is miserable. We can drain an abscess in clinic under local anaesthetic, usually the same day, 7 days a week including weekends, with fees published in advance. For chronic disease we assess the extent, explain the surgical options honestly with their trade-offs, arrange definitive surgery through our CQC-registered partners, and offer laser hair removal to reduce recurrence.
Private pilonidal sinus assessment in East London
A pilonidal sinus is a small tract in the skin near the top of the buttock cleft that can become blocked, infected and painful, sometimes forming an abscess. A private GP in East London can assess it, treat infection, and arrange drainage of an abscess, while our minor surgery service and specialist referral cover longer-term surgical treatment where the problem keeps coming back. Ongoing wound care supports healing. A hot, swollen, very painful lump may be an abscess needing prompt attention through our urgent care service. Tower Bridge Hospital is on Whitechapel Road in East London, a short journey from Canary Wharf and the City, with same-day appointments and no referral required.
Pilonidal sinus in London: common questions
What causes a pilonidal sinus?
Hair and debris become trapped in the skin near the buttock cleft, forming a tract that can block and become infected; it is more common in younger adults.
How is an infected pilonidal sinus treated?
An abscess usually needs drainage, sometimes with antibiotics; recurrent disease is treated with a planned surgical procedure.
Will it come back?
It can recur, so alongside treatment we advise on hair removal and hygiene to reduce the chance.
Can I be seen the same day?
Yes — same-day assessment is available most days, which is important if an abscess has formed.
Abscess drained in clinic, usually the same day
7 days a week including weekends, published fees.