What is a Pilonidal Cyst?
A pilonidal cyst is a subcutaneous infection and inflammatory condition that occurs when hair follicles penetrate the skin, creating an epithelialized sinus tract or cyst containing hair, typically located in the sacrococcygeal (tailbone) region. 1, 2
Pathophysiology and Location
The condition develops when a pore forms and hairs become drawn deeper within it, ultimately creating a sinus tract with surrounding chronic inflammation 1. While the sacrococcygeal region is the classic location, pilonidal cysts can rarely occur in other areas including the scalp, clitoris, and other body sites 3, 2.
Clinical Characteristics
- Demographics: More prevalent in obese, hirsute (hairy) males 1
- Typical age: Young adults, with mean age around 22-25 years 4, 5
- Presentation: Subcutaneous cyst with chronic inflammation, often with purulent drainage when infected
Clinical Significance for Diagnosis
When evaluating recurrent abscesses at a previous infection site, pilonidal cyst should be considered as a local cause requiring specific management 6. The IDSA guidelines specifically recommend searching for pilonidal cysts when patients present with recurrent abscesses, as identifying and treating the underlying structural problem is curative 6.
Key Distinction from Simple Abscesses
Pilonidal disease represents a foreign body reaction with chronic inflammation 7, not just a simple abscess. This distinction is critical because:
- Simple incision and drainage alone leads to high recurrence rates
- Definitive treatment requires addressing the sinus tract and hair follicles
- The condition requires different management than typical skin abscesses
Management Implications
The primary treatment is surgical excision of the affected tissue 1, 8. Various approaches exist including excision with primary closure, healing by secondary intention, or minimally invasive endoscopic techniques 4, 8. Adjunctive treatments like laser/intense pulsed light therapy for hair removal may reduce recurrence 7.