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Pilonidal sinus

A pilonidal sinus is a small hole at the top of your bottom, between your buttocks. Treatment is usually only needed if it becomes infected.

An infected pilonidal sinus is red, painful and may bleed or leak pus.

An infected pilonidal sinus is treated with antibiotics. The pus may also need to be drained. In some cases, you may need surgery.

It's not clear what causes a pilonidal sinus. A skin problem, pressure or friction may cause hair between the buttocks to be pushed inwards.

Read more on the NHS website.

An infected pilonidal sinus is red, painful and may bleed or leak pus.

Check if you have an infected pilonidal sinus

Most people with a pilonidal sinus do not notice it unless it becomes infected and causes symptoms.

An infection will cause pain and swelling, and a pus-filled abscess can develop.

See what an infected pilonidal sinus looks like

An infected pilonidal sinus in the cleft at the top of the buttocks.An infected pilonidal sinus is red, painful and may bleed or leak pus.

Read more on the NHS website.

An infected pilonidal sinus is treated with antibiotics. The pus may also need to be drained. In some cases, you may need surgery.

Self-care

Treatment is not needed if there are no signs of infection. A "watch and wait" approach will be recommended.

It's very important to keep the area between your buttocks clean by showering or bathing regularly.

Do not shave the affected area unless a GP advises you to.

Medical treatments

Treatment for an infected pilonidal sinus will depend on:

  • your symptoms
  • the size of the sinus
  • whether it's your first sinus or it keeps coming back

A pilonidal sinus abscess will need treatment with antibiotics. The pus inside will also probably need to be drained.

There are a number of treatment options for a pilonidal sinus that keeps coming back and that's painful, bleeding or leaking discharge. Your doctor will discuss these with you.

In most cases you'll be offered painkillers, such as paracetamol and anti-inflammatories to help reduce pain and swelling.

Read more on the NHS website.

It's not clear what causes a pilonidal sinus. A skin problem, pressure or friction may cause hair between the buttocks to be pushed inwards.

Read more on the NHS website.