Pilonidal Sinus Disease
Pilonidal disease causes swelling, pain, and sometimes drainage near the top of the buttocks crease — close enough to the anal area that it’s sometimes described, and mistaken, as a hemorrhoid problem. It’s a genuinely separate condition, involving different tissue and a different cause.
- A pilonidal cyst or sinus forms in the natal cleft (the crease between the buttocks), typically a short distance above the anus — not at the anal opening itself, where hemorrhoids occur.
- It’s thought to be caused by hair becoming trapped under the skin in this area, leading to irritation and, sometimes, infection.
- Most common in young adults, and roughly twice as common in men.
- An infected pilonidal abscess usually needs to be drained — it won’t resolve with hemorrhoid creams or sitz baths alone.
Where it is, and why the location matters
The key distinguishing feature of pilonidal disease is location: it develops in the natal cleft — the crease between the buttocks — typically at or near the tailbone, a short distance above the anus rather than at the anal opening itself. Hemorrhoids, by contrast, occur right at the anus or just inside it. If what you’re feeling is more toward the tailbone than right at the anal opening, pilonidal disease is worth considering as a possibility distinct from a hemorrhoid.
What causes it
The exact cause isn’t fully settled, but the leading explanation involves hair becoming trapped under the skin in this area — sometimes from loose hair working its way in, sometimes from hair follicles becoming irritated by friction and pressure. This triggers a local inflammatory reaction that can form a cyst, and if it becomes infected, an abscess and eventually a sinus tract (a small tunnel under the skin, sometimes with an opening to the surface).
Risk factors include prolonged sitting, obesity, excess body hair in the area, a family history of the condition, and friction from tight clothing — historically common enough among people who sat for long periods (including military jeep drivers) that it picked up the nickname “jeep disease.”
Symptoms
- Pain and swelling in the area above the anus, often worse with sitting
- A small dimple, pit, or opening in the skin, sometimes only noticeable during a flare
- Redness and tenderness
- Drainage of fluid or pus, sometimes foul-smelling, if infected
- In more significant infections: fever and fatigue alongside local symptoms
A quiet, uninfected pilonidal sinus can cause minimal or no symptoms for long stretches — flares tend to happen when the area becomes irritated or infected.
Treatment
Treatment depends on whether the area is currently infected:
- No active infection: often managed with hygiene measures and hair removal in the area (shaving or other methods), sometimes without any procedure needed.
- Acute abscess: usually needs to be drained — a minor in-office procedure that typically relieves pain quickly. Antibiotics may be used alongside drainage in some cases, but generally don’t replace it when an abscess is present.
- Recurrent disease: for people with repeated flares, a surgical procedure to remove the sinus tract is often recommended to reduce recurrence, with several surgical approaches available depending on the extent of the disease.
None of these are things hemorrhoid creams, sitz baths alone, or over-the-counter treatments will resolve if infection or a persistent sinus tract is present.
When to see a doctor
- Any new swelling, pain, or drainage in the area above the anus, especially if it’s worsening
- Fever, spreading redness, or significant tenderness — signs of a potentially significant infection
- Recurrent flares in the same area, even if each one seems to resolve on its own
This page is for general education. Pilonidal disease is generally managed by a general or colorectal surgeon and often requires an in-person exam to distinguish from other causes of swelling in the area.