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Pilonidal sinus: patterns and care

Published 23 February 2026 ·Last reviewed 23 February 2026 by the editorial team ·How we create our content

At a glance

A pilonidal sinus is a small tunnel or cavity that forms in the skin at the top of the buttock crease, near the tailbone. The word “pilonidal” means “nest of hair” — loose hairs are thought to work their way into the skin, causing irritation and eventually a tract or pocket.

This condition is common in younger adults, particularly those in their late teens through thirties. People who sit for long periods, have more body hair in the area, or have a deeper natal cleft may be more likely to develop one.

This page covers what people commonly experience, what tends to help or make things worse, and when to seek care.

What people commonly experience

  • A small dimple or pit at the top of the buttock crease that may go unnoticed for some time
  • Pain, tenderness, or swelling near the tailbone — sometimes appearing suddenly
  • Redness and warmth over the area during a flare-up
  • Drainage of fluid or pus, which may have an unpleasant smell
  • Difficulty sitting comfortably, especially on hard surfaces
  • Symptoms that come and go — some people describe quiet periods followed by painful flare-ups

Acute flares vs chronic sinus

Acute flare-ups often involve a rapid increase in pain and swelling. The area may become an abscess — a collection of pus that feels hot and extremely tender. Some abscesses drain on their own. Others need medical drainage.

Chronic pilonidal sinus is when the tract persists over time. People may notice ongoing or intermittent drainage, recurring infections, or discomfort that never fully resolves between flare-ups. Chronic cases are more likely to be discussed in terms of surgical options.

Treatment options people report

  • Conservative care — keeping the area clean and dry, removing hair from the area (shaving or other methods), and warm compresses during mild flares.
  • Incision and drainage — a doctor drains the abscess. This provides relief but the sinus tract may remain.
  • Surgery — several surgical approaches exist, ranging from excision with open healing to flap procedures. The best option depends on the individual case. Your doctor can walk you through what they recommend and why.
  • Ongoing hair removal — many people report that keeping the area free of loose hair helps reduce recurrence after treatment.

What tends to help

  • Keeping the area clean and dry
  • Regular hair removal around the natal cleft — people commonly mention shaving, depilatory creams, or laser hair removal
  • Avoiding prolonged sitting when possible, or using a cushion
  • Warm compresses or sitz baths during mild discomfort
  • Wearing loose, breathable clothing
  • Maintaining a healthy weight — this is sometimes mentioned as helpful for reducing pressure on the area

What tends to make things worse

  • Prolonged sitting, especially on hard surfaces
  • Tight clothing that causes friction in the area
  • Allowing hair to accumulate in the natal cleft
  • Ignoring early signs of a flare-up
  • Sweating and moisture buildup in the area

Talking to your doctor

If you are considering seeing a doctor, it can help to note:

  • When you first noticed symptoms
  • How often flare-ups occur and how long they last
  • Whether you have had any drainage and what it looks like
  • What you have already tried
  • How symptoms affect your daily life — sitting, working, exercising
  • Whether anyone in your family has had a similar condition

Many people feel self-conscious about discussing this area of the body. Doctors see pilonidal sinuses regularly and can help you find the right approach.

If you experience severe pain, heavy bleeding, fever, or symptoms that concern you, seek medical care.

Common questions

What is a pilonidal sinus?

A pilonidal sinus is a small tunnel or cavity that forms in the skin at the top of the buttock crease, near the tailbone. It can fill with fluid, hair, or debris and may become infected, forming an abscess. It is a common condition, particularly in younger adults.

Does a pilonidal sinus go away on its own?

Some people experience a single flare-up that settles with conservative care. Others find it becomes a recurring or chronic issue that may need medical or surgical treatment. Timelines and outcomes vary widely between individuals.

When to seek care Heavy bleeding or feeling faint? Get emergency help now. Emergency: 911

Not sure how urgent it is? Get help today.

  1. Emergency

    Heavy bleeding, black tarry stools, feeling faint, severe pain or trouble breathing.

    Call 911 or go to the ER.

  2. Today

    Fever, pain getting worse, a hot swollen lump, or trouble passing urine.

    Call your doctor or go to urgent care.

  3. Soon

    Bleeding or bowel changes nobody has checked, or anything lasting 3 weeks.

    Book a doctor’s appointment.

Feeling overwhelmed? Call or text 988, any time.

See all the signs

For this topic, get medical advice if you notice:

  • Rapidly increasing pain, redness, or swelling near the tailbone
  • Fever or feeling generally unwell alongside a painful lump
  • Foul-smelling drainage that is getting worse
  • Red streaks spreading outward from the affected area
  • Pain that is severe enough to affect sleep or daily activities
  • A flare-up that has not responded to warm compresses or basic self-care within a few days

Recording how you feel is not the same as being checked. These are the signs that need a doctor’s attention.

Call 911 or go to the emergency room now if you have:

  • bleeding that will not stop, a lot of blood (the toilet water turns red, or you pass large clots), or any bleeding with feeling faint or dizzy
  • fainting, a racing heart or trouble breathing
  • confusion or slurred speech, extreme shivering, no urine in a day, or blotchy skin
  • sudden severe belly pain, or a swollen, hard belly with vomiting or not passing stool or gas
  • you cannot pass urine at all, or your bladder feels full and painful and you can’t empty it
  • redness, swelling or severe pain spreading quickly around your anus, genitals or groin, especially with a fever or feeling very ill
  • a fever with a painful swelling near your anus if you have diabetes or a weakened immune system (for example, from chemotherapy or transplant medicines)
  • black, tarry stools

Call your doctor or go to urgent care today (or the ER if you can’t be seen today) if you have:

  • a temperature of 100.4°F (38°C) or higher, chills, vomiting, or feeling generally unwell
  • pain that is getting worse over days, or severe pain that stops you sitting or sleeping
  • a hot, swollen or very tender lump near your anus or at the top of the crease between your buttocks, or foul-smelling discharge
  • trouble urinating
  • bleeding that is getting heavier or more frequent, or blood mixed into your stool
  • feeling much more tired than usual, looking pale, or getting out of breath more easily than you used to
  • not passing stool for several days, or new belly pain

Make an appointment with your doctor if:

  • you have never had these symptoms checked by a doctor or nurse — whatever your age
  • you have had rectal bleeding for more than 3 weeks
  • your bowel movements have been looser, thinner or more frequent than usual for 3 weeks or more, or you have lost weight without trying
  • symptoms have not settled after a week or so, or keep coming back
  • you notice a new lump near your anus, between your buttocks or in your belly, or an itch or discharge that does not clear
  • you have new leakage or trouble controlling your bowels
  • you are 45 or over, or have a family history of bowel cancer or inflammatory bowel disease, and any of these symptoms are new for you

If you are unsure, it is always reasonable to ask. If things feel overwhelming, call or text 988 (Suicide & Crisis Lifeline) or chat at 988lifeline.org, any time. If you don’t feel safe, call 911.

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