Role of Clarithromycin in Treating Skin Infections
Clarithromycin is an effective treatment option for specific types of skin infections, particularly those caused by nontuberculous mycobacteria, but it is not considered a first-line agent for common skin and soft tissue infections.
Indications for Clarithromycin in Skin Infections
Nontuberculous Mycobacterial Skin Infections
Mycobacterium marinum ("fish tank granuloma"):
- Clarithromycin is a first-line agent, typically used in combination therapy 1
- Recommended regimen: Clarithromycin plus ethambutol for 3-4 months (continue treatment for 1-2 months after symptom resolution) 1
- For deeper infections (osteomyelitis): Add rifampin to the clarithromycin/ethambutol combination 1
Mycobacterium chelonae skin infections:
- Clarithromycin (100% susceptibility) is the cornerstone of treatment 1
- For serious skin infections: Combination therapy with clarithromycin 500mg twice daily plus a second agent based on susceptibility testing for at least 4 months 1
- For disseminated cutaneous disease: Clarithromycin monotherapy (500mg twice daily for 6 months) has shown 92% cure rate 1
Rapidly growing mycobacteria (M. fortuitum, M. abscessus):
Other Skin Infections
- Standard skin and soft tissue infections:
Limitations and Considerations
Not First-Line for Common Skin Infections
- Current guidelines from the Infectious Diseases Society of America do not list clarithromycin as a first-line agent for common skin infections 1
- For methicillin-resistant Staphylococcus aureus (MRSA) skin infections, recommended oral options include:
- Clindamycin, trimethoprim-sulfamethoxazole, tetracyclines, or linezolid 1
Pharmacokinetic Considerations
- Clarithromycin concentrations in soft tissues may be insufficient for pathogens with MICs higher than 0.125 mg/liter 4
- The 500mg twice daily dosing regimen may be ineffective against less susceptible organisms 4
Resistance Concerns
- Bacterial strains resistant to erythromycin are generally also resistant to clarithromycin 5
- Increasing macrolide resistance among common pathogens may limit future clinical usefulness 6
Advantages of Clarithromycin
- Better gastrointestinal tolerability compared to erythromycin 5
- Twice-daily dosing schedule improves compliance compared to four-times-daily erythromycin 5
- Formation of an active 14-hydroxy metabolite enhances antimicrobial activity 5
- Greater in vitro activity than erythromycin against certain pathogens, including mycobacteria 5
Clinical Decision Algorithm
For suspected or confirmed nontuberculous mycobacterial skin infection:
- Use clarithromycin as part of combination therapy
- For M. marinum: Clarithromycin + ethambutol (± rifampin for deep infections)
- For M. chelonae: Clarithromycin + second agent based on susceptibility
For common bacterial skin infections (cellulitis, impetigo, etc.):
- Use first-line agents per guidelines (β-lactams, clindamycin, TMP-SMX)
- Consider clarithromycin only if:
- Patient has allergy/intolerance to first-line agents
- Susceptibility testing confirms sensitivity
- First-line treatments have failed
For complicated skin infections requiring hospitalization:
- Follow IDSA guidelines for empiric coverage with vancomycin, linezolid, daptomycin, or telavancin 1
- Clarithromycin is not recommended as first-line therapy
Conclusion
While clarithromycin has demonstrated efficacy in treating various skin infections, its primary role in dermatology is for nontuberculous mycobacterial infections, particularly M. marinum and M. chelonae. For common bacterial skin infections, other antibiotics are generally preferred as first-line agents according to current guidelines.