Pilonidal sinus is a chronic inflammation in one or more sinuses in the midline of the natal cleft caused by hair and debris. It is more common in overweight males between puberty and age 40. Risk factors include obesity, local trauma, sitting for long periods, and a deep natal cleft. Acquired pilonidal sinus occurs when hair breaks the skin in the natal cleft, collects debris, and grows deeper causing infection. Symptoms include intermittent pain and drainage in the natal cleft area. Diagnosis is usually clinical based on examination finding sinuses, pits, or abscesses in the natal cleft. Treatment depends on severity, with incision and drainage for abscesses and

1. Pilonidal sinus
Mohammed AlHinai

2. Pilonidal disease :
Chronic inflammation in one or more sinuses in the midline of the natal cleft that
contain hair and debris. The tract lined with granulation tissue as resulting from
chronic infection and the superficial part of sinus lined with squamous epithelium.
Risk factors:
• Overweight/obesity
• Local trauma or irritation
• Sedentary lifestyle or prolonged sitting
• Deep natal cleft
• Family history
Etiology
Congenital
rarely occur as
embryological
causes
Acquired
common as occur in location subject to local
trauma from hair :
- hand of barbers.
- sheep sheareres
- dog groomers
- area exposed to hair as umbilicus and scalp

4. Person sits or bend cause natal cleft stretch and damaging or breaking
hair follicle lead to opening or pore formation ( pit)
The pore collect debris and serve as good environment for root of
hair to grow which become embedded later on
During movement, skin drawn over natal cleft created
negative pressure in subcutaneous space
Causes drawing of hair deeper into pore and grow
in opposite directing
Hair act as foreign
body reaction and
prevent healing
process
Friction occur and cause
recurring or chronic
inflammation as hair
retained in affected area
Form sinuses and discharge when
the area infected
pathogenesis

7. Clinical features :
History :
• Age : more common between puberty and 40 years old are rare before puberty or
over 40 yr.
• Sex : more common among male and more develop in dark-haired and hirsute male.
Symptoms
Acute exacerbation :
• Intergluteal pain :
- sudden onset of mild to severe
throbbing pain.
- Increase by sitting or performing
activities that stretch the skin
overlying the natal cleft (eg, bending,
sit-ups).
• intermittent swelling as well as
mucoid purulent, and/or bloody
drainage in the area.
Chronic pilonidal sinus:
• recurrent or persistent
drainage and pain.
• Fever and malaise are
generally associated with an
undrained abscess.

8. Clinical features :
Physical examination:
- one or more primary pores (pits) in the midline of the natal cleft and/or a painless
sinus opening
- The skin over sinuses abscess is red and tender.
- patients with acute or chronic disease, a tender mass or sinus draining mucoid,
purulent, and/or bloody fluid can be identified when pressure done
- Secondary tracts or pits can be identified lateral to the midline in patients with
chronic or persistent complex disease.
Diagnosis
Clinical diagnosis Laboratory :
- leukocytosis may indicate an
undrained abscess in the acute or
chronic clinical setting.

9. Differential diagnosis:
• Perianal abscess
• Hidradenitis suppurativa (chronic follicular occlusive disease involving the
intertriginous skin of the axillary, groin, perianal, perineal, and
inframammary regions)
• Anorectal fistula
• Perianal complications of Crohn disease
• Skin abscess, furuncle, carbuncle
• Folliculitis

10. Management :
Acute exacerbation
due to abscess :
• incision and
drainage (I&D)
procedure at the
time of
presentation.
Chronic or recurrent
disease:
• surgical excision of
all sinus tracts.
Asymptomatic incidental
sinus :
• surgical excision is not
typically performed for
patients who have never
experienced an acute flare.
• Conservative management :
- Hygiene
- hair control
- observation for signs of
acute infection.