Pilonidal sinus

Question 1

Define pilonidal sinus.

Answer 1

When a forceful insertion of hairs into the skin of the natal cleft in the sacrococcygeal area promotes chronic inflammatory reaction causing an epithelialised sinus.

Sinuses may be multiple and communicate via deep cavity. Chronic discharge usually occurs and infection may supervene and lead to an abscess.

Question 2

What is the pathophysiology of pilonidal sinus?

Answer 2

Initially thought to be congenital but now thought to be acquired.

Broken hair is driven into the skin of the natal cleft by a rolling action of the buttocks. This provokes a foreign body type reaction and chronic inflammation results in a mature sinus.

Question 3

What is the aetiology and risk factors for pilonidal sinus?

Answer 3

Hair in the natal cleft

more common in hairy (hirsute) people

People with multiple, loose, stiff hairs within a deep and narrow natal cleft with macerated or broken skin are most at risk.

Question 4

What age and sex is most commonly affected? How common is it?

Answer 4

Male (80%)

16-40 years (mean age 20years and hairy)

Estimated prevalence 26 per 100,000 in US

Question 5

What are the symptoms of pilonidal sinus?

Answer 5

• Sacrococcygeal pain and swelling, discharge (+/- fever if abscess)
• Skin maceration
• Hx of prior treated abscess or spontaneous rupture of one
• Male aged 16-40 years.

Question 6

What are the signs of pilonidal sinus on examination?

Answer 6

Sacrococcygeal discharge, sinus tracts (one or more around the midline of the natal cleft)

Skin maceration due to chronic irritation of the sinus discharge

Question 7

What investigations would you do for pilonidal sinus?

Answer 7

none - clinical diagnosis

Question 8

How do you manage pilonidal sinus?

Answer 8

If asymptomatic - hair removal and local hygiene

If symptomatic +/- abscess

• Surgical closure of the sinus,
• antibiotic therapy - amoxicillin (500mg TDS 5-7days),
• +/- hair removal by laser depilation
• +/- pain relief (abscess should not be painful once drained)

If recurrent disease, repeat surgery and hair removal.

Question 9

What are the complications of pilonidal sinus?

Answer 9

Post operative collection deep to sutures - post-surgical suture removal may be required to achieve drainage.

Necrotising fasciitis - fever and toxaemia should raise suspicion

Question 10

What is the prognosis with pilonidal sinus?

Answer 10

Recurrence rates variable but average 7% - depends on surgical closure.