Pilonidal Sinus

What pilonidal disease is

Pilonidal disease affects the natal cleft — the crease between the buttocks, just above the tailbone. Hair and debris become trapped in the skin of the cleft, provoking a foreign-body reaction and chronic inflammation. Small midline openings, called pits, form; from these, tracks can run under the skin and discharge onto the surface, sometimes to one side.

It is most common in young adults, more often men, and is associated with a deep cleft, abundant hair, prolonged sitting and friction. Despite the old name of a congenital cyst, it is generally understood as an acquired condition driven by hair and friction in the cleft, rather than by poor personal hygiene.

How it presents

Presentation ranges widely, and the range is the point, because treatment differs at each stage.

Some people have pits and no symptoms at all. Some have chronic disease: intermittent discharge of pus or blood, a damp patch on clothing, aching after long periods sitting or driving, and one or more openings that come and go. Others present with an acute abscess: rapidly increasing pain, a hot tender swelling, and sometimes fever.

Recurrent disease — symptoms returning after previous surgery — is treated as a distinct problem, because the choice of operation is different from the choice for a first presentation.

How the diagnosis is made

The diagnosis is clinical. The natal cleft is examined for midline pits, for openings to one side, for induration along a track, and for the tenderness and fluctuance that indicate an abscess. Scans are not needed in straightforward disease; imaging is reserved for unusual presentations or when another diagnosis is being considered.

Two other conditions are worth separating from pilonidal disease, because their treatment differs. A perianal abscess or fistula sits close to the anal canal rather than in the natal cleft above the tailbone. Hidradenitis suppurativa causes recurrent inflamed nodules and tracks in the groin, axillae and buttocks, and is a skin disease that needs medical treatment alongside any surgery. Where the pattern does not fit, or where disease behaves unusually, further assessment is arranged rather than repeating the same operation.

Asymptomatic pits

Pits found incidentally, causing no symptoms, do not need an operation. Prophylactic surgery for asymptomatic disease is not recommended. Observation and ordinary cleft hygiene are appropriate. After haircuts, loose hairs can be washed away from the cleft. Routine shaving or depilation is not required by current ESCP guidance to prevent recurrence.

Acute abscess

The standard treatment for an acute pilonidal abscess is lateral incision and drainage, and pain settles quickly afterwards. Antibiotics alone do not replace drainage of a true pilonidal abscess. They may be added when there is significant surrounding cellulitis, systemic illness, immunosuppression or another specific clinical indication. Drainage alone is not definitive treatment: a proportion of patients will have persistent or recurrent disease and will need a planned procedure later. Major excisional or flap surgery is usually considered separately once acute inflammation has settled, although selected minimally invasive or endoscopic approaches may be considered as an alternative in experienced settings.

Chronic disease

For chronic pilonidal disease, several approaches exist, and their trade-off is between the chance of healing and the length and difficulty of recovery.

Minimally invasive and sinus-preserving techniques remove or destroy the tracks through small openings, and are distinct from one another: pit picking is generally used for limited disease, endoscopic pilonidal sinus treatment (EPSiT) visualises and treats the tracks through a fine scope, and laser sinus ablation uses laser energy to close the track from within. Laser sinus ablation is a treatment for the tracks themselves and is a different procedure from laser hair epilation, which targets hair follicles. These approaches can offer smaller wounds, less early pain and a faster return to normal activity in selected disease, but comparative recurrence and treatment-failure estimates vary between techniques and much of the evidence is of low or very low certainty. They are reasonable first options for many people with limited disease, particularly when a quick return to work matters, provided the uncertainty around recurrence and the possible need for further treatment is understood.

Excisional surgery removes the affected tissue. How the wound is then managed matters more than the excision itself. Where a wound is closed, guidelines advise off-midline closure — techniques such as the Karydakis, Bascom cleft-lift or Limberg flap — rather than closure in the midline, because midline closure is associated with higher rates of wound failure and recurrence. Excision left open to heal by secondary intention avoids a midline scar but requires prolonged dressing care over weeks to months.

Recurrent disease after previous surgery needs reassessment of the pits, previous scars, cleft anatomy and extent of disease. Off-midline flap reconstruction is important for many recurrent or complex cases, while selected recurrent patients may still be suitable for endoscopic or other minimally invasive treatment; referral to a surgeon experienced in these techniques is appropriate.

After treatment

There is no evidence that preoperative hair removal affects outcome, and postoperative hair removal from the natal cleft by any method — shaving, depilatory cream, or laser hair epilation — is not a necessity to reduce recurrence. Guidelines differ on routine hair removal: ESCP 2024 does not consider postoperative hair removal necessary to reduce recurrence and finds insufficient evidence to recommend laser hair epilation routinely, whereas ASCRS 2019 allows shaving or laser hair epilation as an adjunct on the basis of low-quality evidence. Showering after a haircut, good cleft hygiene and removal of loose hairs are reasonable, and any planned hair-removal programme should be individualised with your surgeon. No recommendation can currently be made for laser hair epilation, or any other hair-removal method, as a primary treatment for pilonidal disease itself. Recurrence remains possible after every technique, including flap procedures, so wound care and follow-up are part of the plan rather than an afterthought. Claims of a scarless or guaranteed permanent cure are not supported by the evidence.