Management of Epidermoid Cysts
Incision and drainage is the recommended treatment for inflamed epidermoid cysts, with complete removal of the cyst wall to prevent recurrence. 1
Diagnosis and Characteristics
- Epidermoid cysts are benign lesions containing cheesy keratinous material and normal skin flora even when uninflamed 2
- They typically present as asymptomatic nodules unless complicated by rupture or infection 2
- When inflamed, they can present as painful, tender swellings that may mimic abscesses 2
- Inflammation typically occurs as a reaction to rupture of the cyst wall and extrusion of contents into the dermis, rather than as a primary infectious process 2
Treatment Algorithm
For Uninflamed Epidermoid Cysts
- Complete surgical excision is the definitive treatment to prevent recurrence 3
- Minimal excision technique is less invasive than complete surgical excision and does not require suture closure 4
- Involves making a 2-3 mm incision
- Expressing the cyst contents through compression
- Extracting the cyst wall through the incision
- Most cases can be performed under local anesthesia with a low complication rate of 2.2% 3
For Inflamed Epidermoid Cysts
- Incision and drainage is the recommended treatment (strong recommendation, high-quality evidence) 1
- Treatment should include:
- Thorough evacuation of the contents
- Probing the cavity to break up loculations
- Covering the surgical site with a dry dressing 2
- Consider postponing complete excision until inflammation has subsided, as inflamed cysts are more difficult to excise 4
Important Considerations
- Gram stain and culture of pus from inflamed epidermoid cysts are not recommended (strong recommendation, moderate-quality evidence) 1
- Systemic antibiotics are rarely necessary unless there are complicating factors such as:
- Multiple lesions
- Cutaneous gangrene
- Severely impaired host defenses
- Extensive surrounding cellulitis
- Severe systemic manifestations of infection 2
- To avoid relapses, the cyst wall must be removed completely 3
Special Populations and Locations
- Epidermoid cysts can occur at any age but are most frequently reported in adults 5
- They occur more often in men than women (approximately 3:2 ratio) 5
- Most common locations include:
- Face (65.0%)
- Trunk (10.9%)
- Scalp (7.9%)
- Neck (7.9%) 5
- Rare genetic disorders with multiple cysts include Gardner and Lowe syndrome 3
Complications and Follow-up
- Potential complications include rupture leading to inflammation and secondary infection 2
- Histological evaluation is necessary only if unusual findings or clinical suspicion of cancer is present 4
- The risk of malignant transformation is extremely rare for typical epidermoid cysts 2