What Is a Pilonidal Cyst?
A clear, medically grounded guide to the painful bump at the top of the buttock crease — what it really is, why it happens, and how it is permanently cured.
A hair-containing sinus — not an ordinary cyst
If you have just been told you have one, you are probably asking what a pilonidal cyst is and why it happened to you. Here is the whole picture at a glance.
What it is
A small sinus, or tunnel, under the skin at the top of the buttock crease.
Why it happens
Loose hair is driven into the deep midline cleft by friction and pressure.
Who gets it
Most often young adults, especially men, and people who sit for long stretches.
How it's cured
Definitive flap-based repair that reshapes the cleft for a durable result.
What Is a Pilonidal Cyst, Exactly?
Despite the name, a pilonidal cyst is not a true cyst. It is a small sinus, or tunnel, that develops under the skin in the natal cleft — the deep groove between the buttocks. The word pilonidal comes from Latin for a “nest of hair,” which is the clue to what is really going on: the tract typically contains loose hairs and skin debris.
When people picture a cyst, they imagine a closed sac. In reality it usually connects to the surface through one or more tiny openings called pits. Through those pits, hair works its way in, the body reacts to it as a foreign object, and inflammation or infection follows.
How a pilonidal cyst forms
Loose hairs, combined with friction and pressure in the deep midline cleft, are driven point-first into the skin — where they trigger a chronic reaction.
Hair collects in the cleft
Loose hairs gather in the warm, dark, moist midline groove at the top of the buttocks.
Friction drives it in
Constant motion and pressure force hair through tiny pits, point-first into the skin.
The body inflames
Buried hair is treated as a foreign object, sparking inflammation and infection.
A sinus tract forms
A tunnel develops around the hair and can flare, drain, and abscess over time.
See us in Los Angeles — or from anywhere
Prefer not to travel for a first opinion? We offer virtual consultations nationwide, so you can review your case with a specialist before you ever come in.
Recognizing the symptoms
Symptoms vary widely — from something barely noticeable to a genuinely painful problem that interferes with sitting, driving, and daily life.
A small dimple, pit, or painless bump at the top of the buttock crease.
Pain, swelling, and redness when the tract becomes inflamed or infected.
Drainage of pus or blood, sometimes with a foul odor.
A tender, fluctuant lump when an abscess forms.
Recurring flares that quiet down and then return weeks or months later.
Discomfort that worsens with prolonged sitting or activity.
Who Is Most at Risk
The condition most commonly appears in young adults between the late teens and thirties, and it is more frequent in men than in women. Several factors raise the risk:
- Being a young adult — the disease peaks after puberty.
- Thick or coarse body hair in the buttock region.
- A deep natal cleft that traps hair and moisture.
- Prolonged sitting — sometimes called “jeep driver’s disease.”
- Friction, sweating, or a family history of the condition.
Risk factors do not guarantee the disease, and having none does not make you immune. They help explain why a given person developed a pilonidal cyst and inform how best to prevent recurrence after treatment.
How It Is Diagnosed
In most cases a specialist can confirm a pilonidal cyst through a simple physical examination. The surgeon inspects the natal cleft for the characteristic midline pits, any secondary openings, and signs of inflammation or drainage.
They will ask about your history of flares, previous abscesses or drainage procedures, and family history. For extensive, branching, or recurrent disease, imaging occasionally helps map how far the tracts extend.
Why the cleft-lift is definitive
Treatment ranges from draining an acute abscess to definitive surgery that corrects the underlying anatomy. Draining relieves pain quickly but leaves the sinus behind — so flares often continue.
At The Pilonidal Institute, board-certified colorectal surgeons Dr. Yosef Nasseri and Dr. Moshe Barnajian specialize in flap-based and cleft-lift repair. The cleft-lift lifts healthy tissue, flattens the deep midline groove, and moves the healing incision off to the side — removing the pits and reshaping the environment that caused the disease.
Because it corrects the anatomy rather than only removing tissue, this approach is associated with consistently low recurrence and a return to light activity typically within one to two weeks. For most patients, it is the most reliable route to a lasting cure.
Explore flap-based treatment →Meet your surgeons
Board-certified colorectal surgeons who treat pilonidal disease constantly — not as an occasional case.
Dr. Yosef Nasseri
A leader in cleft-lift and flap-based pilonidal repair, focused on durable cures and a smooth recovery.
Dr. Moshe Barnajian
Specializes in anatomy-correcting repair that removes the pits and reshapes the cleft to prevent recurrence.
What Happens If It Is Left Untreated
Because the sinus tract does not close on its own, an untreated pilonidal cyst tends to follow a frustrating cycle of flare, drainage, brief calm, and flare again. Over time, that pattern can grow more complicated rather than simply staying the same.
Repeated abscesses and painful flare-ups that interrupt work and sleep.
New pits and branching tracts that enlarge the affected area.
Accumulating scar tissue that can complicate later surgery.
Do not settle for a quick drainage alone
If a pilonidal cyst has flared more than once, ask about definitive, anatomy-correcting repair rather than repeated drainage that never ends the cycle. Addressing the disease while it is still limited generally means a simpler procedure and a smoother recovery than waiting for it to become chronic.
Back to the life you paused
A durable cure means getting back to work, exercise, and daily life — without planning around the next flare.
Why specialization matters
Pilonidal disease is best managed by colorectal specialists who treat it constantly — rather than a one-time urgent-care drainage that leaves the tract intact.
The whole picture
We evaluate the depth of your cleft, the number of tracts, prior treatments, and your lifestyle.
A lasting result
That perspective is what turns a good procedure into a durable, low-recurrence cure.
Close follow-up
For Los Angeles patients, easy return visits during healing are an added advantage.
Frequently asked questions
What is a pilonidal cyst in simple terms?+
Is a pilonidal cyst dangerous?+
Can a pilonidal cyst go away on its own?+
What actually causes a pilonidal cyst?+
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Now that you know what a pilonidal cyst is, let our specialists recommend the most durable path to a cure.
Schedule your consultation today — in person in Los Angeles or by virtual visit from anywhere.
(310) 627-2330