What is the recommended treatment for dermatophytosis?

Treatment of Dermatophytosis

For dermatophyte infections of the skin (tinea corporis, tinea cruris, tinea pedis), oral terbinafine 250 mg daily is the first-line systemic treatment, with topical terbinafine 1% cream as first-line for localized disease. 1

Topical Therapy for Localized Skin Infections

• Topical terbinafine 1% cream applied twice daily for 1 week is highly effective for tinea pedis, tinea corporis, and tinea cruris, achieving mycological cure rates exceeding 90% 2
• Topical therapy is superior to other topical agents: more effective than clotrimazole 1% cream (which requires 4 weeks of treatment), bifonazole, and oxiconazole 3, 2
• Topical treatment alone is not recommended for tinea capitis or onychomycosis, where systemic therapy is required 1

Systemic Therapy for Extensive or Resistant Skin Infections

First-Line: Terbinafine

• Oral terbinafine 250 mg daily for 2-4 weeks for tinea corporis/cruris and tinea pedis 1, 3
• Terbinafine is fungicidal against dermatophytes with superior efficacy compared to griseofulvin and ketoconazole 1, 3
• Achieves mycological cure rates exceeding 80% in cutaneous dermatophyte infections 4, 3

Second-Line: Itraconazole

• Itraconazole 200 mg daily or 400 mg daily pulse therapy can be used if terbinafine is contraindicated 1
• Less effective than terbinafine for dermatophyte infections but has broader spectrum including some yeasts 1

Alternative: Griseofulvin

• Griseofulvin 500-1000 mg daily is an older option with lower efficacy and higher relapse rates compared to terbinafine 1
• Remains first-line for tinea capitis caused by Microsporum species (particularly M. canis) where it is more effective than terbinafine 1, 5

Tinea Capitis-Specific Recommendations

• Terbinafine is first-line for Trichophyton species (T. tonsurans, T. violaceum): weight-based dosing for 2-4 weeks 1
  • <20 kg: 62.5 mg daily
  • 20-40 kg: 125 mg daily

  • 40 kg: 250 mg daily

• Griseofulvin is first-line for Microsporum species (M. canis, M. audouinii): 15-20 mg/kg/day for 6-8 weeks 1
• Topical therapy alone is ineffective; oral therapy is mandatory 1

Onychomycosis Treatment

• Terbinafine 250 mg daily is first-line for dermatophyte nail infections 1, 6
  • Fingernails: 6 weeks of treatment 1, 6
  • Toenails: 12-16 weeks of treatment 1, 6
• Terbinafine is superior to itraconazole for dermatophyte onychomycosis, with complete cure rates of 55% vs 26% at 72 weeks, and significantly lower relapse rates (23% vs 53%) 1
• Itraconazole 200 mg daily for 12 weeks continuously, or pulse therapy 400 mg daily for 1 week per month (2 pulses for fingernails, 3 pulses for toenails) is second-line 1
• Mycological confirmation is mandatory before starting systemic therapy 1, 6

Monitoring and Safety

Baseline Testing Required

• Liver function tests and complete blood count before initiating terbinafine 1, 7, 8, 6
• More vigilant monitoring in patients with pre-existing liver disease, heavy alcohol use, or concomitant hepatotoxic medications 1, 6

Contraindications to Terbinafine

• Active or chronic liver disease 1, 8, 6
• History of allergic reaction to oral terbinafine 8, 6
• Lupus erythematosus 1, 8

Key Adverse Effects to Warn Patients About

• Taste disturbance (including permanent taste loss): patients should discontinue immediately if this occurs 1, 6
• Hepatotoxicity: warn patients to report nausea, anorexia, fatigue, vomiting, right upper abdominal pain, jaundice, dark urine, or pale stools 6
• Smell disturbance including loss of smell, which may be permanent 6
• Common mild effects: headache, gastrointestinal upset (nausea, diarrhea) 1

Critical Pitfalls to Avoid

• Never start systemic antifungal therapy without mycological confirmation (KOH preparation, fungal culture, or nail biopsy) 1, 6
• Do not use terbinafine for Candida infections—it has only fungistatic activity against yeasts; itraconazole is preferred 1, 4
• Recognize that terbinafine has minimal drug interactions compared to azoles, with only cytochrome P450 2D6 interactions being significant 1, 7
• Re-evaluate patients 3-6 months after treatment initiation, as optimal clinical effect occurs months after mycological cure due to nail outgrowth 7, 6
• In treatment failure with onychomycosis (20-30% failure rate), consider poor compliance, subungual dermatophytoma requiring partial nail removal, or switching to alternative agent 1