ConditionSkin, hair & nails
Pilonidal Disease (Pilonidal Cyst, Sinus and Abscess)
Pilonidal disease is a skin condition in the cleft between the buttocks, near the tailbone, in which loose hairs push into the skin and cause inflammation and infection. It can appear as small pits in the skin, a painful swollen abscess, or a chronic sinus that keeps draining pus or blood. It is most common in young men aged 15 to 35, especially those who are hairy, sit for long periods or carry extra weight. Abscesses need drainage, and recurring disease is treated with minimally invasive procedures or surgery.
Also called: Pilonidal cyst, pilonidal sinus, pilonidal abscess, jeep driver's disease
At a glance
- What it is
- Hair and debris trapped in the skin of the buttock crease, causing inflammation, infection and tracts.
- Who gets it
- Mostly men aged 15 to 35. Risk factors include hairiness, prolonged sitting, obesity and a deep crease.
- Forms
- Painless pits, acute abscess, chronic draining sinus.
- Treatment
- Abscess drainage, hair removal, minimally invasive procedures, or excision surgery.
- Recurrence
- Common, so hair control and wound care matter.
When to get help
Call 911 or go to the ER
- Rapidly spreading redness, severe pain, fever and feeling very unwell, especially with diabetes or a weak immune system (possible spreading infection)
See a doctor within a day or two
- A painful, red, swollen lump at the top of the buttock crease, especially with fever (possible abscess)
- Increasing pain, redness or pus after pilonidal surgery
Book a routine appointment
- Small pits or holes in the buttock crease that drain blood, pus or fluid
- A recurring lump or ongoing drainage after previous treatment
- Itching, discomfort or odor at the top of the crease
Usually safe to manage at home
- Small pits without pain or discharge: keep the area clean, dry and free of hair, and watch for changes
What causes pilonidal disease
The exact mechanism is debated, but the leading explanation is that loose hairs, often from the head, back or buttocks, are driven into the skin of the natal cleft by friction and pressure when sitting or moving. The body reacts to the hair as a foreign object, causing inflammation and small pits. Bacteria cause infection, forming an abscess. Repeated inflammation creates tunnels (sinuses) under the skin.
Risk factors
- Male sex and age 15 to 35
- Thick, coarse or abundant body hair
- Prolonged sitting, such as drivers and office workers
- Obesity
- A deep buttock crease
- Friction from tight clothing
- Poor hygiene and sweating
- Family history
Symptoms
Pits without symptoms
Small holes in the midline of the buttock crease, sometimes with hairs protruding.
Acute pilonidal abscess
- A painful, tender, red, swollen lump near the top of the buttock crease
- Pain when sitting or walking
- Pus or blood drainage, sometimes foul-smelling
- Fever in some cases
Chronic pilonidal sinus
- Ongoing or intermittent drainage from one or more openings
- Recurring tender swelling
- Skin irritation from discharge
Diagnosis
Pilonidal disease is diagnosed by examination. A clinician looks for midline pits, sinus openings, abscesses and their relationship to the anus. Imaging is not usually needed, but may be used for complex or recurrent disease, or to rule out other conditions.
Conditions that look similar
| Condition | How it differs |
|---|---|
| Perianal abscess or anal fistula | Located near the anus, often with pain during bowel movements |
| Hidradenitis suppurativa | Recurrent lumps in several areas, including armpits and groin |
| Folliculitis or a boil | Superficial, around a hair follicle, not in the midline crease |
| Tailbone conditions | Pain over the bone without skin openings |
Treatment
Acute abscess
- Incision and drainage: a small cut under local anesthetic to release pus. This gives quick relief. The wound is cleaned and packed or covered.
- Antibiotics only if there is spreading skin infection or the person is at higher risk.
Chronic or recurrent disease
- Minimally invasive procedures: removing pits and hair through small openings (such as pit picking, endoscopic or laser techniques), with quicker recovery and less pain.
- Excision surgery: removing the affected tissue and sinus tracts. The wound may be left open to heal from the base over weeks, closed in the midline, or closed with an off-midline flap technique (such as the Bascom cleft lift or Karydakis procedure), which flattens the crease and reduces recurrence.
- Hair removal: shaving, depilatory creams or laser hair removal around the area reduces recurrence after treatment.
Wound care
Keep wounds clean, use dressings as advised, shower daily, and keep the area free of hair. Healing after open wound surgery can take several weeks to months.
Outlook
Pilonidal disease often becomes less active after age 30 to 40. Recurrence after treatment is common, ranging widely by procedure. Off-midline closure techniques and ongoing hair removal lower the risk. With appropriate treatment and care, most people heal.
Prevention
- Keep the buttock crease clean and dry.
- Remove hair from the area regularly or consider laser hair removal.
- Avoid sitting for long periods. Stand and move around regularly.
- Maintain a healthy weight.
- Wear loose, breathable clothing.
Frequently asked questions
What causes a pilonidal cyst?
Pilonidal cysts are caused by loose hairs being pushed into the skin of the buttock crease by friction and pressure, particularly when sitting. The body reacts to the hair, causing inflammation and pits, which can become infected and form abscesses and tunnels under the skin.
Can a pilonidal cyst go away on its own?
Small pits without symptoms may stay quiet for years. An infected abscess may burst and drain on its own, but it usually comes back because the hair and tract remain. Recurring or chronic disease usually needs a procedure to remove the affected tissue.
How is a pilonidal abscess treated?
A pilonidal abscess is treated by incision and drainage under local anesthetic, which relieves pain quickly. Antibiotics are added only if there is spreading infection. Once the abscess settles, a definitive procedure may be recommended to prevent recurrence.
Will a pilonidal cyst come back after surgery?
It can. Recurrence rates vary by procedure and are higher when the wound is closed in the midline. Off-midline flap techniques, keeping the area free of hair and good wound care reduce the chance of recurrence.
Sources
This guide was written from current patient and clinical guidance, including:
- American Society of Colon and Rectal Surgeons: Clinical Practice Guidelines for the Management of Pilonidal Disease
- American Academy of Family Physicians: Pilonidal disease
- MedlinePlus: Pilonidal cyst
- NHS: Pilonidal sinus
- Mayo Clinic: Pilonidal cyst