What is the treatment for severe tinea?

Treatment of Severe Tinea Infections

For severe tinea infections, oral antifungal therapy is required, with terbinafine preferred for Trichophyton species and griseofulvin preferred for Microsporum species. 1

Medication Selection Based on Causative Organism

For Trichophyton Species:

• Terbinafine (first-line):
  • < 20 kg: 62.5 mg daily for 2-4 weeks
  • 20-40 kg: 125 mg daily for 2-4 weeks

  • 40 kg: 250 mg daily for 2-4 weeks 1

For Microsporum Species:

• Griseofulvin (first-line):
  • < 50 kg: 15-20 mg/kg/day for 6-8 weeks

  • 50 kg: 1 g/day for 6-8 weeks 1

  • FDA labeling recommends 10 mg/kg daily for pediatric patients and 0.5 g daily for adults, with individualized dosing 2

Alternative Agents:

• Itraconazole: 50-100 mg/day for 4 weeks or 5 mg/kg/day for 2-4 weeks (effective against both Trichophyton and Microsporum) 1
• Fluconazole: Effective against T. violaceum, T. verrucosum, and M. canis 1
• Voriconazole: More potent than griseofulvin or fluconazole, but limited by cost 1

Treatment Approach Based on Clinical Presentation

For Severe Tinea with Kerion, Scale, Lymphadenopathy, or Alopecia:

1. Begin treatment immediately while awaiting confirmatory mycology 1
2. Continue treatment until mycological clearance is achieved, not just clinical improvement 1
3. For T. tonsurans infections, screen and treat all family members and close contacts 1

Treatment Duration

• Trichophyton infections: 2-4 weeks with terbinafine 1
• Microsporum infections: 6-8 weeks with griseofulvin 1
• Treatment must continue until the infecting organism is completely eradicated as indicated by appropriate clinical or laboratory examination 2

Adjunctive Therapy

• Topical antifungal agents may be used as adjunctive therapy but are insufficient as monotherapy for severe tinea 1
• Topical ketoconazole can be used for tinea corporis, cruris, pedis, and versicolor, but requires longer treatment periods (2-6 weeks depending on location) 3
• Sporicidal shampoos (e.g., selenium sulfide) can aid in removing scales and decreasing spread 4

Important Considerations and Pitfalls

1. Avoid ketoconazole oral therapy due to risk of hepatotoxicity 1

2. Treatment failure pitfalls:

   • Inadequate duration of therapy
   • Incorrect diagnosis
   • Non-compliance with medication
   • Failure to treat asymptomatic carriers with high spore load 1

3. Monitoring:

   • The endpoint of treatment should be mycological cure, not just clinical improvement 1
   • For short courses (≤4 weeks) of newer antifungals, routine liver enzyme monitoring is generally unnecessary 4

4. Comparative efficacy:

   • Studies have shown similar efficacy between griseofulvin (6 weeks) and newer antifungals like terbinafine, itraconazole, and fluconazole (2-3 weeks) for Trichophyton species infections 5
   • For tinea imbricata, griseofulvin and terbinafine demonstrated superior efficacy compared to itraconazole and fluconazole 6

5. General measures:

   • Implement hygiene measures to control sources of infection or reinfection 2
   • Children receiving appropriate therapy can attend school or nursery 1

The choice of antifungal agent should be guided by the causative organism, with terbinafine preferred for Trichophyton and griseofulvin for Microsporum species. Treatment must continue until complete eradication of the infection is achieved.