What is the recommended treatment for cutaneous microsporidiosis?

Treatment of Cutaneous Microsporidiosis

Albendazole is the first-line treatment for cutaneous microsporidiosis, administered at 7.5 mg/kg orally twice daily (maximum 400 mg twice daily) until clinical resolution. 1

Treatment Algorithm

First-line therapy:

• Albendazole: 7.5 mg/kg orally twice daily for patients <60 kg; maximum dose 400 mg orally twice daily
• Continue treatment until clinical resolution of skin lesions
• Albendazole is particularly effective for infections caused by Encephalitozoon species and other microsporidia species 1

For Enterocytozoon bieneusi infection (if identified):

Albendazole has limited efficacy against Enterocytozoon bieneusi. In these cases:

• Fumagillin: 20 mg orally three times daily for 2 weeks 1
  • Note: Fumagillin is not available in the United States
  • Monitor for bone marrow toxicity (thrombocytopenia and neutropenia)

Alternative therapies (for treatment failures or intolerance):

• Nitazoxanide: Has shown activity against Enterocytozoon bieneusi 1
  • Adults: 500-1000 mg twice daily
  • Children 4-11 years: 200 mg twice daily
  • Children 1-3 years: 100 mg twice daily

Special Populations

Immunocompromised patients:

• Longer duration of therapy may be required
• HIV-infected patients may need lifelong suppressive therapy with albendazole if immunosuppression cannot be reversed 1
• Immune reconstitution through antiretroviral therapy is crucial for HIV-infected patients

Children:

• Albendazole: 7.5 mg/kg orally twice daily (maximum 400 mg twice daily) 1
• Nitazoxanide (for E. bieneusi):
  • Children 4-11 years: 200 mg twice daily
  • Children 1-3 years: 100 mg twice daily

Pregnant women:

• Limited data available
• Consider delaying treatment if infection is non-severe
• Consult with specialists regarding risk-benefit assessment

Monitoring and Follow-up

• Clinical improvement should be evident within 2-4 weeks
• Monitor for adverse effects of albendazole (elevated liver enzymes, neutropenia)
• For patients on fumagillin, monitor complete blood count regularly due to risk of bone marrow toxicity

Important Considerations

Species identification

Microsporidial species identification is important as treatment efficacy varies:

• Albendazole works well for Encephalitozoon species
• Fumagillin has broader activity against both Encephalitozoon species and Enterocytozoon bieneusi 2

Common pitfalls

1. Failure to identify the microsporidial species can lead to ineffective treatment
2. Inadequate duration of therapy, especially in immunocompromised patients
3. Overlooking immune reconstitution in HIV-infected patients
4. Expecting complete cure with albendazole in E. bieneusi infections

Microsporidiosis represents an important opportunistic infection, particularly in immunocompromised patients 3. The clinical course depends on the immune status of the host and the site of infection. While gastrointestinal infection is most common, cutaneous manifestations require prompt and appropriate treatment to prevent complications and improve quality of life.