Why it starts
Loose or ingrown hair can irritate skin in the cleft and lead to infection or sinus formation.
Hair entry
Sweat and friction
Long sitting
Pilonidal Sinus Info
Pilonidal Sinus Causes & Risk Factors
Pilonidal sinus usually develops in the cleft near the tailbone, where hair, friction, pressure and skin debris can trigger infection and sinus openings.
Patient Guide
Pilonidal Sinus Causes & Risk Factors
Learn pilonidal sinus causes and risk factors, including hair, friction, deep cleft, sweating, sitting and recurrence.
Who is at risk
Risk may rise with thick hair, deep natal cleft, obesity, sweating and prolonged sitting.
Desk or driving work
Recurrent boils
Family tendency
How recurrence is reduced
Treatment must be paired with hygiene, hair control and pressure reduction where appropriate.
Cleft hygiene
Hair removal plan
Follow-up after drainage or surgery
Related Reading
Explore Related Topics
Continue learning about pilonidal sinus — each linked topic adds important clinical context to help you prepare for your consultation.
FAQ
Frequently Asked Questions
Is pilonidal sinus caused by poor hygiene?
No. Hygiene helps prevention, but hair, anatomy and friction are major contributors.
Can sitting cause pilonidal sinus?
Long sitting can increase pressure and irritation, especially with other risk factors.
Can it come back?
Yes. Recurrence can happen without hair control, hygiene and suitable treatment.
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Care Notes
Common near tailbone cleft
Hair and friction contribute
Recurrence prevention matters
Medical references used for this guide
This page is educational and does not replace a clinician's examination. References reviewed include ASCRS pilonidal disease patient information, and Cleveland Clinic pilonidal cyst guide.