Treatment of Pilar Cysts
For asymptomatic pilar cysts, surgical excision is the definitive treatment and should be performed to prevent complications including infection, inflammation, and rare malignant transformation. For infected cysts, incision and drainage is the primary treatment, with antibiotics reserved only for patients with systemic signs of infection 1.
Treatment Algorithm by Clinical Presentation
Asymptomatic Pilar Cysts
- Complete surgical excision is recommended as the only definitive treatment 2, 3
- Perform excision under local anesthesia
- Submit all excised tissue for histopathological examination to rule out proliferating trichilemmal cysts, which carry a rare malignancy risk 4, 5
- Early excision prevents future complications: infection, rupture, inflammation, and malignant transformation 6, 3
Infected/Inflamed Pilar Cysts
Incision and drainage is the primary treatment 1. The IDSA guidelines specifically address this:
- Perform incision and drainage as first-line therapy (strong recommendation, high-quality evidence) 1
- Do NOT routinely culture inflamed epidermoid cysts (strong recommendation) 1
- Antibiotics are NOT routinely needed after drainage 1
When to Add Antibiotics (Adjunct to Drainage):
Add antibiotics active against S. aureus ONLY if the patient has:
- SIRS criteria present: Temperature >38°C or <36°C, heart rate >90 bpm, respiratory rate >24/min, or WBC >12,000 or <4,000 cells/µL 1
- Markedly impaired host defenses 1
- Use MRSA-active antibiotics (vancomycin, doxycycline, clindamycin, or TMP-SMX) if SIRS present 1
Cosmetically Concerning Cysts
- Complete surgical excision under local anesthesia 6
- Multiple cysts can be removed in staged procedures if needed 6
- Scrotoplasty or reconstructive techniques may be necessary for large or multiple cysts in certain locations 7
Critical Pitfalls to Avoid
Do not treat infected cysts with antibiotics alone—this is inadequate. Drainage is essential 1. The guidelines emphasize incision and drainage as the cornerstone of treatment, not antimicrobial therapy.
Do not assume all scalp cysts are benign—always send excised tissue for histopathology. Proliferating pilar tumors can rarely undergo malignant transformation 5, and distinguishing benign from proliferating variants requires pathological examination 4.
Do not perform needle aspiration—this has only 25% success rate overall and <10% with MRSA infections 1. Formal incision and drainage is required.
Post-Excision Management
- Cover surgical site with dry sterile dressing—this is easier and more effective than packing 1
- Wound packing causes more pain without improving healing 1
- Monitor for recurrence, though complete excision typically prevents this 2, 3
Special Considerations
For recurrent cysts at the same site, search for underlying causes such as foreign material or retained cyst wall 1. Incomplete excision is the most common cause of recurrence, emphasizing the importance of complete surgical removal with intact cyst wall 2.