Pilonidal Disease

What is pilonidal disease?

Pilonidal disease is a common, chronic inflammatory condition affecting the skin in the crease of the buttocks (the natal cleft). It begins with one or more small pits or openings in the skin, which can become infected and form a painful abscess (a collection of pus). While once thought to be a congenital condition, it is now widely believed to be an acquired process. The leading theory suggests that loose hairs, under pressure and friction from sitting and movement, penetrate the skin and create a foreign body reaction, leading to inflammation, sinus tract formation, and potential infection.

Common Symptoms

The presentation of pilonidal disease can vary widely:

• Asymptomatic Pits: Some people may only have one or several small, painless openings (pits or sinuses) in the midline of their natal cleft without any other symptoms.
• Pain, Redness, and Swelling: If the area becomes infected, a tender, red, swollen lump may form. This is a pilonidal abscess, and it is often very painful, especially when sitting.
• Drainage: The pits or a swollen abscess may drain pus or bloody fluid, which can be clear, cloudy, or bloody and may have a foul odor.
• Fever: In the case of an acute abscess, systemic symptoms like fever and malaise can occur.

What causes pilonidal disease?

Pilonidal disease is thought to be an acquired condition caused by a combination of factors that force hair to penetrate the skin in the natal cleft.

• Loose Hairs: Shed hairs from the head, back, and buttocks collect in the deep natal cleft.
• Friction and Pressure: Activities like prolonged sitting create friction and pressure that can drive these hairs into the skin, much like a splinter.
• Foreign Body Reaction: The body treats the embedded hair as a foreign object, triggering an inflammatory response that leads to the formation of a sinus tract or a cyst.
• Infection: The sinus can become blocked and infected with skin bacteria, leading to a painful abscess.

Risk factors that contribute to this process include:

• A deep natal cleft
• Being male (though it is also common in females)
• A family history of the condition
• Occupations or lifestyles that involve a lot of sitting (e.g., truck drivers, office workers)
• Obesity
• Coarse or stiff body hair (hirsutism)
• Poor hygiene or excessive sweating

How is pilonidal disease diagnosed?

The diagnosis of pilonidal disease is almost always made based on a physical examination. A doctor will examine the skin in the crease of your buttocks and can typically identify the characteristic midline pits. If an abscess is present, it will appear as a tender, red, swollen area, which is often located just to one side of the midline. Imaging tests like CT scans or MRIs are generally not needed unless the diagnosis is unclear or there is suspicion of a very deep or complex infection.

How is pilonidal disease treated?

Treatment depends on whether you have an acute abscess or chronic, recurring disease. The guiding principle is that the treatment should not be more debilitating than the disease itself.

• Acute Abscess: The primary treatment for a pilonidal abscess is incision and drainage. A doctor will numb the area with local anesthetic and make a small incision to drain the pus. This procedure provides immediate pain relief. The incision is typically made slightly off the midline to promote better healing. The wound is usually left open to continue draining and heals over several weeks.

• Chronic or Recurrent Disease: For patients with recurring infections or persistent drainage, surgery to remove the sinus tracts is often recommended. There are many different surgical options, and the best choice depends on the extent of the disease and the surgeon's expertise.

  • Excision and Healing by Secondary Intention: The sinus tracts are surgically removed, and the wound is left open to heal from the bottom up. This has a lower recurrence rate than primary closure but requires several weeks to months of regular dressing changes.
  • Excision and Primary Closure: The diseased tissue is removed, and the wound is closed with stitches. This allows for faster healing but has a higher risk of wound infection and recurrence, especially if the wound is closed in the midline.
  • Flap Procedures: More complex procedures like the Karydakis flap, Limberg flap, or cleft lift procedure are designed to not only remove the diseased tissue but also to flatten the natal cleft and move the scar away from the midline. These procedures have the lowest recurrence rates but are more extensive operations.

Self-Care and Prevention

Good personal hygiene is the most important step in managing pilonidal disease and preventing recurrences.

• Keep the area clean: Wash the natal cleft daily with a mild soap.
• Keep the area dry: Moisture can encourage bacterial growth. Thoroughly dry the area after bathing.
• Hair removal: Regularly removing hair from the natal cleft is one of the most effective ways to prevent recurrence. Options include shaving, using depilatory creams, or laser hair removal.
• Avoid prolonged sitting: If your job requires sitting, take frequent breaks to stand and walk around.
• Weight management: If you are overweight, losing weight can reduce the depth of the natal cleft and decrease friction.

Is a pilonidal cyst a type of cancer?
No, pilonidal disease is a benign inflammatory condition. In extremely rare cases, a very long-standing, chronic pilonidal wound can develop into a type of skin cancer (squamous cell carcinoma), but this is exceptionally uncommon.

Will it go away on its own?
An acute pilonidal abscess will not go away on its own and requires drainage. Chronic pilonidal sinuses will not disappear and are likely to cause recurrent problems over time unless they are surgically removed or ablated.

Why does pilonidal disease come back after surgery?
Recurrence happens when the underlying factors that caused the disease in the first place—a deep cleft, hair, and friction—are still present. Procedures that leave a scar in the midline of the natal cleft have a higher recurrence rate because the new scar can act as a site for new hair penetration. This is why flap procedures that flatten the cleft and move the scar off the midline are often preferred for recurrent disease.

• Bhama AR, Davis BR. Pilonidal Disease and Hidradenitis Suppurativa. In: Steele SR, Hull TL, Hyman N, Maykel JA, Read TE, Whitlow CB, eds. The ASCRS Textbook of Colon and Rectal Surgery. 4th ed. Springer; 2022:293-310.
• Mayo Clinic. Pilonidal cyst. Published July 21, 2021. Accessed October 12, 2025. https://www.mayoclinic.org/diseases-conditions/pilonidal-cyst/symptoms-causes/syc-20376329
• American Society of Colon and Rectal Surgeons. Pilonidal Disease. Accessed September 28, 2026. https://fascrs.org/Web/Patients/Diseases-and-Conditions/A-Z/Pilonidal-Disease.aspx