Pilonodal Sinus

Question 1

What is a Pilonodal sinus?

Answer 1

Obstruction of natal cleft hair follicles ~6cm above the anus

Question 2

Describe the aetiology of pilonodal sinus

Answer 2

Ingrowing of hairs incites a foreign body inflammatory reaction + may cause secondary tracks to open laterally +/- abscesses with foul-smelling discharge.
Intermittent negative pressure will draw in more hair + perpetuate the cycle

Question 3

Describe the epidemiology of pilonodal sinuses

Answer 3

COMMON
Affects 0.7% of young adults
Male ages 16 – 40 years
Obese, Caucasians, Asians, Middle East + Mediterraneans at high risk

Question 4

List 4 risk factors for pilonodal sinus

Answer 4

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

Question 5

What is the nature of symptoms of pilonodal sinus?

Answer 5

Painful natal cleft
Discharging
Swelling
Often recurrent

Question 6

List signs of pilonodal sinus

Answer 6

Midline openings or pits between the buttocks
Hairs may protrude from the swelling
If infection or abscess, swelling will become tender
May be fluctuant + discharge pus or blood-stained fluid on compression
Skin Maceration due to chronic irritation caused by sinus discharge

Question 7

What investigations are needed for a pilonodal sinus?

Answer 7

NONE needed

DIAGNOSIS IS CLINICAL

Question 8

What investigations could be performed for a pilonodal sinus?

Answer 8

Bloods: to check for signs of infection- raised WCC  
Fasting glucose (diabetics are at risk)

Question 9

Describe the management of asymptomatic primary pilonodal sinuses

Answer 9

Local hair removal

Local hygiene

Question 10

List 4 complications of pilonodal sinuses

Answer 10

Pain
Infection
Abscess: typically occurs in the natal of hairy individuals
Recurrence

Question 11

What is the prognosis of pilonodal sinuses?

Answer 11

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

Question 12

Describe the management of symptomatic primary pilonodal sinuses without abscess

Answer 12

Sinus excision or primary off-midline closure (on either side of natal cleft)
Abx: amoxicillin/clavulanate

Question 13

Describe the management of symptomatic primary pilonodal sinuses with abscess

Answer 13

Incision + drainage

Abx: amoxicillin/clavulanate