Treatment of Trichophyton tonsurans Infections
For T. tonsurans infections, oral terbinafine is the first-line treatment due to superior efficacy against Trichophyton species, with weight-based dosing for 2-4 weeks achieving >90% cure rates. 1
First-Line Oral Antifungal Therapy
Terbinafine (Preferred for T. tonsurans)
- Weight-based dosing: 1
- <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
- Efficacy: Achieves 94% effective treatment rate at 12 weeks for T. tonsurans infections 2
- Recent adult data: 83.2% clinical cure rate in adults with T. tonsurans tinea capitis 3
- Contraindications: Active or chronic liver disease, lupus erythematosus 4
- Monitoring: Baseline liver function tests recommended, especially with pre-existing hepatic abnormalities 5
Griseofulvin (Alternative, UK-licensed for children)
- Dosing: 1
- <50 kg: 15-20 mg/kg/day for 6-8 weeks
50 kg: 1 g/day for 6-8 weeks
- Efficacy: 92% effective treatment rate but requires longer duration than terbinafine 2
- Note: Remains the only licensed treatment for tinea capitis in children in the UK, though suspension formulation is no longer licensed 1
- FDA indication: Specifically indicated for T. tonsurans infections 6
Second-Line Therapy
Itraconazole
- Dosing: 50-100 mg daily for 4 weeks, or 5 mg/kg/day for 2-4 weeks 1
- Efficacy: 86% effective treatment rate for T. tonsurans 2, though one study showed only 40% success at 100 mg/day for 4 weeks 7
- Advantage: Active against both Trichophyton and Microsporum species 1
- Drug interactions: Enhanced toxicity with warfarin, terfenadine, astemizole, sertindole, midazolam, digoxin, cisapride, ciclosporin, and simvastatin 1
- Licensing: Not licensed in UK for children ≤12 years with tinea capitis 1
Fluconazole (Third-Line)
- Efficacy: 84% effective treatment rate for T. tonsurans 2
- Limitations: Not licensed for tinea in children <10 years in UK; less cost-effective than terbinafine 1, 5
Treatment Algorithm for Failure
When initial therapy fails, consider these factors in order: 1
- Assess compliance and absorption: Verify medication adherence and proper administration
- If clinical improvement but positive mycology: Continue current therapy for additional 2-4 weeks 1
- If no clinical improvement: Switch to second-line agent
Critical Management Principles
Family and Contact Screening
- Screen all family members and close contacts for T. tonsurans, as >50% may be affected with occult disease 1
- Treat all positive cases to prevent recurrence, as failure to treat the whole family results in high recurrence rates 1
- Asymptomatic carriers with high spore load generally warrant systemic treatment 1
Environmental Decontamination
- Clean all fomites (hairbrushes, combs, towels) with disinfectant or 2% sodium hypochlorite solution 1, 5
- Avoid sharing personal items and limit skin-to-skin contact with infected individuals 1
Treatment Endpoint and Monitoring
- Mycological cure, not clinical response, is the definitive endpoint 1, 4
- Follow-up with repeat mycology sampling monthly until clearance is documented 1
- Common pitfall: Clinical appearance may improve while infection persists 8
School/Activity Attendance
- Children receiving appropriate systemic and adjunctive topical therapy should be allowed to attend school or nursery 1
Concomitant Tinea Corporis Considerations
When T. tonsurans causes both scalp and body lesions:
- Concomitant tinea corporis increases treatment failure risk (odds ratio 3.9) 3
- Treat both sites simultaneously with the same oral antifungal regimen
- Consider longer treatment duration (4 weeks rather than 2 weeks) when extensive body involvement present 3
In Vitro Susceptibility Data
Recent susceptibility testing of T. tonsurans isolates shows: 9
- Lowest MICs: Tolnaftate (0.022 µg/mL), itraconazole (0.026 µg/mL), terbinafine (0.033 µg/mL)
- Highest MIC: Fluconazole (12.540 µg/mL), supporting its position as third-line therapy