Pilonidal Sinus & Abscess

Recognition and general-practice management of pilonidal disease.

Background

Pilonidal disease is chronic inflammation of the sacrococcygeal fold driven by retained hair and debris in the natal cleft, almost always over the buttock/gluteal region. Incidence is around 26 per 100,000, peaking in the second and third decades, and men are affected about twice as often as women. Higher BMI, coarse hair and a deep natal cleft are additional risk factors. Only 50–75% of chronically inflamed cavities actually contain a hair shaft on examination — absence of visible hair doesn’t exclude the diagnosis.

Clinical presentation

Asymptomatic sinus pits found incidentally need reassurance and hygiene advice only — the disease often settles once the patient passes their 30s.

Acute pilonidal abscess presents with pain, swelling, erythema and a tender lump in or near the natal cleft. Antibiotic value in an uncomplicated acute abscess is not well established; add a course (flucloxacillin is the most widely used) only if there is associated cellulitis, immunodeficiency or concurrent systemic illness — not for every abscess as a matter of routine.

Chronic pilonidal sinus presents with intermittent pain, swelling and discharge at the base of the spine, usually without constitutional symptoms, and often a history of previous abscesses that drained spontaneously or were incised off the midline.

Acute abscess

Source control is the mainstay — needle aspiration, drainage without curettage, or drainage with curettage of the cavity to clear hair and debris. See Abscess Incision & Drainage for general technique; a pilonidal abscess follows the same principles. Reserve antibiotics for the indications above rather than prescribing them alongside every drainage.

Chronic and recurrent disease

Chronic or recurrent pilonidal sinus needs a surgical referral — this is not a general-practice procedure — but the GP conversation about what to expect matters, since recurrence with further pain, embarrassment and time off work is common and drives a lot of the patient’s distress.

Options a surgeon may offer:

• Lay open of the sinus — simplest and quickest, but has the highest recurrence rate and needs an extended period of wound care while healing by secondary intention.
• Karydakis flap — excises the sinus to the sacral fascia and closes with a lateralised tissue flap. The most successful traditional technique, with a recurrence rate as low as 1–5% in various series, at the cost of a longer, more involved procedure and a real risk of post-operative infection or seroma.
• Bascom cleft lift — a less invasive variant aimed at removing secondary hair follicles and lateralising the natal cleft; shortest healing time of the flap procedures (around 3.5 weeks) and less post-operative pain, but a higher reported recurrence (around 15%).
• Limberg flap — a rhomboid excision and transposition flap with lower rates of post-operative pain, infection and seroma than the Karydakis method, at the cost of a bigger scar and a longer, prone-position procedure.
• Endoscopic pilonidal sinus treatment (EPSiT) — a fistuloscope visualises and debrides the tract without an open wound. Shorter recovery (2–3 weeks), no painful packing, and an acceptable reported recurrence rate (~5%) with the advantage of being repeatable if it fails — but still lacks the long-term outcome data of the established flap procedures.

Prevention

Good hygiene is the mainstay of prevention and worth stressing to every patient with pilonidal disease, regardless of what treatment they’ve had. Vacuum dressings after a lay-open procedure haven’t been shown to beat simple dressings. On hair removal: only laser hair removal has evidence of reducing recurrence — shaving or depilatory cream is associated with higher recurrence, likely from skin trauma and inconsistent long-term use, so don’t recommend either as a substitute for laser.