Patient story - ABC Listen Up


Dr Manon Kolkman from Denmark has very kindly shared her hygiene protocol for those with pilonidal sinus.


A pilonidal sinus is a clump (or nest) of hair under the skin - first described in 1833.

It occurs due to a combination of three factors:

1. stiff shed hairs (and perhaps hair cut hair) with scales like a drill bit

2. accumulation of hair in the crack (natal cleft) 

3. rolling movement of buttocks (pushes the hair through the skin like a pin)




  • acute: abscess (boil) - if this does not settle with antibiotics, surgical drainage of the infection may be required.

  • longstanding: pain, discharge (pus and blood) and bad smell

  • recurrence of symptoms after surgery can be frustrating and is not uncommon


Natural history

  1. What the future holds for your pilonidal sinus is not known - this makes treatment decisions difficult.

  2. Some sinuses may remain minimally symptomatic.

  3. Sometimes an abscess may form requiring antibiotics and surgical drainage. About 50% of abscesses will recur.

  4. For others, the disease appearance and symptoms progress.



If you look carefully, there will be one or more tiny indents (pits) or openings (sinuses) in the depths of the natal cleft. Hair may protrude from these.

Typically, there is a small lump or scar higher and slightly to the left. This is where hair accumulates (and sometimes exits - secondary sinus).



The condition starts in adolescence, at a younger age in girls than boys. Possibly hair changes in response to sex hormones.

While old research proposed a sucking mechanism to draw hairs in, there is ample evidence that a lose hair is able to penetrate intact skin - helped along by scales which ensure hair always rolls/advances in one direction (root-end first).


Medical and Surgical Information

No special tests are required to make the diagnosis but occasionally Magnetic Resonance Imaging may be necessary to distinguish a pilonidal sinus from a fistula-in-ano.

pilonidal sinus will only heal if the causative actors are eliminated: hair, cleft, force.

The modified Karydakis flap is a lens shaped excision of midline sinuses and the nearby secondary opening. The axis of the excised skin is displaced 2cm from the midline to make sure the scar is away from the midline. A 1cm thick flap is sutured in two layers and the skin closed with a dissolving stitch. Usually, drains are not necessary.

While the Bascom 2 (or Cleft Lift) operation is technically different (different sequence of surgical steps and depth of excision),

the end result (long off midline scar with a flattened crack) is essentially the same. 

The only operations which result in a scar that does not cross the midline are the Bascom 2 and Karydakis flap.

Scars from all other flaps cross the midline at least once, which may result in a wound complication or disease recurrence.


The Karydakis flap is often performed as a day case under General Anaesthesia.

For the majority, healing takes approximately 2 - 3 weeks.


15% of patients (1 in 7) will develop a minor wound infection near the anus but this typically heals itself within a few weeks. This rate is higher if you are overweight. Sometimes additional surgery is needed.

Recurrence of the pilonidal sinus occurs in about 3 % of patients after the Karydakis flap.



The local anaesthetic injected during surgery will last for around 6 hours

Tablet pain relief will then be needed.

The dressing is waterproof and usually stays on for 5 - 7 days.

Some patients choose to apply a new dressing after this time for another 7 days.

Patients naturally take it easy for the first 2-3 weeks after surgery - restrict activities which are uncomfortable or painful.



Dr Manon Kolkman from Denmark has very kindly shared her hygiene protocol for those with pilonidal sinus.