Mupirocin Will Not Help Treat a Myxoid Cyst
Mupirocin is an antibiotic indicated exclusively for bacterial skin infections caused by Staphylococcus and Streptococcus species and has no role in treating myxoid cysts, which are non-infectious cystic lesions arising from the distal interphalangeal joint. 1, 2
Why Mupirocin Is Not Indicated
Myxoid cysts are not infections - they represent ganglions of the distal interphalangeal joint caused by leakage of joint fluid, mucoid degeneration of connective tissue, or synovial fluid herniation, not bacterial pathogens 3, 4
Mupirocin targets bacteria, not structural lesions - it demonstrates activity against Staphylococcus aureus (including MRSA) and Streptococcus species for superficial skin infections like impetigo, infected wounds, and secondarily infected lesions 1, 2
The pathophysiology is mechanical, not infectious - myxoid cysts result from joint fluid communication with the skin surface, often associated with osteoarthritis and osteophytes in elderly patients 3, 4
Appropriate Treatment for Myxoid Cysts
Surgical intervention is the definitive treatment with the highest cure rates (94-95% for finger lesions) 3, 5
The most effective surgical approach involves identifying the communication between the joint and cyst using methylene blue dye injection, then ligating this connection without tissue excision - this achieves cure in 89% of cases with minimal scarring 3
Non-surgical options include observation for asymptomatic lesions, needle puncture and drainage (though recurrence is common), sclerotherapy (77% healing rate), cryotherapy (72% healing rate), or corticosteroid injections (61% healing rate) 4, 5
Toe lesions have lower cure rates (57%) compared to finger lesions (94%), making them more likely to relapse regardless of treatment method 3
Common Pitfall to Avoid
- Do not confuse myxoid cysts with infected skin lesions - while mupirocin is appropriate for secondarily infected eczema, ulcers, or lacerations 1, 6, a myxoid cyst presenting as a clear, gelatinous, cystic lesion at the distal interphalangeal joint requires mechanical intervention, not antibiotic therapy 3, 4