Pilonidal Sinus

Question 1

Definition

Answer 1

An abnormal epithelium-lined tract filled with hair that opens onto the skin surface, most commonly in the natal cleft

Question 2

Aetiology

Answer 2

• Caused by shed or sheared hairs penetrating the skin and inciting and inflammatory reaction and sinus development
• Intermittent negative pressure will draw in more hair and perpetuate the cycle

Question 3

Risk factors

Answer 3

o Hirsutism
o Spending a long time sitting down
o Occupational (e.g. hairdressers may develop interdigital pilonidal sinus)

Question 4

Epidemiology

Answer 4

• COMMON

* Affects 0.7% of young adults

Question 5

Presenting symptoms

Answer 5

• Painful natal cleft
• Discharging swelling
• Often recurrent

Question 6

Signs on physical examination

Answer 6

• Midline openings or pits between the buttocks
• Hairs may protrude from the swelling
• If infection or abscess, the swelling will become tender
• It may be fluctuant and discharge pus or blood-stained fluid on compression

Question 7

investigations

Answer 7

• NONE needed

• Bloods - to check for signs of infection
o Raised WCC
o Fasting glucose (diabetics are at risk)

Question 8

Management plan

Answer 8

• Acute Pilonidal Abscess
o Incision and drainage

• Chronic Pilonidal Sinus
o Excision under general anaesthesia with exploration

• Prevention
o Good hygiene
o Shaving

Question 9

Possible complications

Answer 9

• Pain
• Infection
• Abscess
• Recurrence

Question 10

Prognosis

Answer 10

• Good with drainage
• Shaving will cure in most cases
• Usually resolves by the age of 40