A pilonidal cyst shows up as a small dimple, pit, or swollen lump near the tailbone, right at the top of the crease between your buttocks. You might notice it only because the area feels tender when you sit, or you might see visible swelling and redness. Some pilonidal cysts cause no symptoms at all until they become infected, at which point the signs become hard to ignore.
What a Pilonidal Cyst Looks Like
The most telling sign is location. A pilonidal cyst is almost always found in the natal cleft, the vertical crease between your buttocks, a few inches above the anus. This location distinguishes it from a perianal abscess, which forms much closer to the anal opening, and from a regular boil, which can appear anywhere on the body.
In its earliest form, you may notice a small pit or dimple in the skin at the top of your buttocks crease. It can look like a pimple. The area around it might be slightly red and warm to the touch. At this stage, many people assume it’s a minor skin irritation and ignore it.
When the cyst grows or becomes inflamed, it forms a noticeable lump under the skin. The swelling can range from pea-sized to several centimeters across. The skin over it often looks tight, shiny, and red. Sitting or any pressure on the tailbone area becomes uncomfortable or outright painful.
Signs of Infection
An uninfected pilonidal cyst can sit quietly for months or even years. The real trouble starts when bacteria get in and an abscess forms. Infected pilonidal cysts produce a distinct set of symptoms:
- Increasing pain: The area becomes progressively more tender, especially when sitting or leaning back. The pain can shift from a dull ache to a sharp, throbbing sensation over a day or two.
- Swelling and redness: The lump grows larger and the surrounding skin becomes inflamed.
- Drainage: Pus or blood may leak from an opening in the skin. This discharge often has a foul smell.
- Fever: A low-grade fever can develop if the infection spreads beyond the cyst itself.
If you notice red streaks spreading outward from the lump, increasing warmth, or a fever alongside the swelling, the infection may be moving into surrounding tissue. That combination calls for prompt medical attention.
What Causes It
A pilonidal cyst forms when a loose hair punctures the skin and becomes embedded. Your body treats the trapped hair as a foreign object and builds a pocket of tissue around it, trying to wall it off. That pocket fills with hair, skin debris, and sometimes bacteria. Friction and pressure from sitting push the hair deeper, which is why the condition tends to develop in the tailbone crease where hair, moisture, and pressure all converge.
Pilonidal disease affects roughly 26 out of every 100,000 people. Men develop it about twice as often as women. The typical age range is late teens through the 30s, though it can occur at any age. You’re at higher risk if you have thick or coarse body hair, sit for long periods (desk jobs, long-distance driving), carry extra weight, have a family history of the condition, or have experienced repeated friction or irritation in the tailbone area.
How It Differs From a Boil or Pimple
A regular boil is an infected hair follicle that can pop up almost anywhere on your body. It forms around a single follicle, comes to a head, and often drains on its own within a week or two. A pilonidal cyst, by contrast, forms deeper under the skin and contains not just one hair but often a tangle of hair and skin debris. It sits in a very specific spot near the tailbone and tends to recur.
Another key difference is the presence of sinus tracts. A pilonidal cyst can develop small tunnels under the skin that connect the cyst to additional openings on the surface. If you notice more than one pit or drainage point in the area, that’s a strong indicator of pilonidal disease rather than a simple boil. A standard pimple or boil won’t create these connecting tunnels.
How Doctors Confirm It
Diagnosis is straightforward. A doctor can typically identify a pilonidal cyst through a visual exam alone. They’ll look for the characteristic pit or dimple near the tailbone, check for swelling and tenderness, and note any drainage. In most cases, no imaging or lab work is needed.
If the presentation is unusual, such as a cyst appearing closer to the anus than expected, a doctor may investigate further to rule out other conditions like a perianal abscess or fistula. Pilonidal sinuses near the anal canal are rare, but they do occur and can be tricky to distinguish from other perianal problems without a closer look.
What to Expect if You Have One
A small, painless pilonidal cyst that isn’t infected may not need immediate treatment. Keeping the area clean, removing hair through shaving or laser hair removal, and avoiding prolonged sitting can sometimes prevent it from progressing.
Once a cyst becomes infected and forms an abscess, it typically needs to be drained. This is a relatively quick procedure, usually done in a doctor’s office under local anesthesia. You’ll feel pressure relief almost immediately, though the area will be sore for days afterward and needs to be kept clean while it heals. Recovery from a simple drainage usually takes a few weeks.
For cysts that keep coming back, a more involved surgical procedure may be recommended to remove the cyst and sinus tracts entirely. Recovery from surgery takes longer, sometimes several weeks to a couple of months depending on the technique used and whether the wound is left open to heal from the inside out or closed with stitches. Pilonidal cysts are known for recurring, so ongoing hair removal and hygiene in the area remain important even after successful treatment.
Who Should Be Especially Alert
If you’re a young man with thick body hair who sits for long stretches during the day, you fit the highest-risk profile for pilonidal disease. Any persistent tenderness, swelling, or dimple near your tailbone is worth checking. The same applies if a close family member has dealt with pilonidal cysts, since there appears to be a genetic component.
People who’ve had one pilonidal cyst before should watch the area closely. Any return of tenderness, drainage, or swelling in the same spot likely signals a recurrence rather than a new, unrelated problem. Early treatment of a recurrence is simpler than waiting for a full abscess to develop.