What is the recommended treatment for tinea (dermatophytosis), including topical and oral options for skin, scalp, and nail infections?

Treatment of Tinea (Dermatophytosis)

For tinea infections, treatment selection depends critically on anatomic site: scalp and nail infections require oral antifungal therapy, while most localized skin infections (corporis, cruris, pedis, manuum) respond to topical agents unless extensive, resistant, or occurring in immunocompromised patients. 1

Diagnostic Confirmation Before Treatment

• Obtain mycological confirmation through potassium hydroxide (KOH) microscopy and fungal culture whenever possible before initiating therapy 1
• Collect specimens by scalpel scraping, hair pluck, brush sampling, or swab depending on the lesion type 2, 1
• Start treatment immediately without waiting for culture results if kerion, severe scaling, lymphadenopathy, or alopecia are present 1
• The definitive endpoint for adequate treatment must be mycological cure (negative microscopy and culture), not just clinical improvement 1, 3

Tinea Capitis (Scalp) - Requires Oral Therapy

Organism-directed therapy provides optimal outcomes, with terbinafine preferred for Trichophyton species and griseofulvin for Microsporum species. 1

For Trichophyton Species (Most Common):

• Terbinafine is the preferred first-line agent with weight-based dosing for 2-4 weeks: 1
  • Children <20 kg: 62.5 mg daily
  • Children 20-40 kg: 125 mg daily
  • Children >40 kg and adults: 250 mg daily

For Microsporum Species:

• Griseofulvin is the preferred agent with dosing for 6-8 weeks: 1
  • Children <50 kg: 15-20 mg/kg/day
  • Children >50 kg and adults: 1 g/day

Special Considerations for Scalp Infections:

• Kerion represents a delayed inflammatory host response, not bacterial infection—do not delay systemic antifungal therapy 1
• Topical or oral corticosteroids may provide symptomatic relief for severe inflammation in kerion 1
• Baseline liver function tests are recommended before initiating terbinafine or itraconazole 2, 1

Tinea Corporis, Cruris, Pedis, and Manuum (Skin)

Topical Therapy (First-Line for Localized Disease):

Apply topical antifungals for mild to moderate infections without extensive involvement: 2, 1

• Clotrimazole cream twice daily for 2-4 weeks 2
• Miconazole cream twice daily for 2-4 weeks 2
• Terbinafine 1% gel once daily for 1-2 weeks 1
• Alternative: Ciclopirox 0.77% cream/gel twice daily for 4 weeks or naftifine ointment twice daily for 4 weeks 1

Treatment duration: Tinea corporis and cruris for 2 weeks; tinea pedis for 4 weeks with azoles or 1-2 weeks with allylamines 4

Oral Therapy (For Extensive, Resistant, or Immunocompromised):

Reserve oral agents for extensive disease, treatment failure, or immunocompromised patients: 1

Terbinafine (Preferred for Trichophyton):

• 250 mg daily for 1-2 weeks for corporis/cruris 2, 1
• 250 mg daily for 2 weeks for pedis 5
• 250 mg daily for 2-4 weeks for manuum 1
• Particularly effective against T. tonsurans with 86% mycological cure rate 2, 1

Itraconazole (Effective for Both Trichophyton and Microsporum):

• 100 mg daily for 15 days with 87% mycological cure rate 2, 1
• Alternative: 200 mg daily for 7 days 5
• Important drug interactions: Enhanced toxicity with warfarin, certain antihistamines, antipsychotics, midazolam, digoxin, and simvastatin 2, 1
• Contraindicated in heart failure 1

Fluconazole (Third-Line Option):

• 50-100 mg daily or 150 mg once weekly for 2-3 weeks 5
• Less cost-effective than terbinafine with limited comparative efficacy data 2

Tinea Unguium (Nails) - Requires Oral Therapy

Oral antifungal therapy is the treatment of choice for onychomycosis, with terbinafine generally preferred over itraconazole due to superior efficacy and shorter treatment duration. 1

Terbinafine (Preferred):

• 250 mg daily with duration based on site: 1
  • Fingernail infections: 6 weeks
  • Toenail infections: 12-16 weeks

Itraconazole (Alternative First-Line):

• Continuous therapy: 200 mg daily for 12 weeks 1
• Pulse therapy: 400 mg daily for 1 week per month (2 pulses for fingernails, 3 pulses for toenails) 1

Critical Monitoring and Follow-Up

• Repeat mycology sampling at the end of standard treatment period and continue monthly until mycological clearance is documented 1, 3
• Monitor liver function with terbinafine and itraconazole, especially with pre-existing hepatic abnormalities or prolonged therapy 1
• Baseline liver function tests and complete blood count are recommended before initiating terbinafine 1
• If clinical improvement occurs but mycology remains positive, continue current therapy for an additional 2-4 weeks 1
• If no initial clinical improvement, switch to second-line therapy 1

Prevention of Recurrence

• Screen and treat all family members, especially with anthropophilic species like Trichophyton tonsurans, as over 50% may be affected 2, 1
• Clean all fomites (hairbrushes, combs, towels) with disinfectant or 2% sodium hypochlorite solution 2, 1
• Avoid skin-to-skin contact with infected individuals and do not share personal items 2, 1
• Wear protective footwear in public bathing facilities, gyms, and hotel rooms 1
• Apply antifungal powders (miconazole, clotrimazole, or tolnaftate) in shoes and on feet to prevent reinfection 1
• Keep affected areas clean and dry 3

Common Pitfalls to Avoid

• Stopping treatment based only on clinical improvement rather than mycological cure 3
• Not considering secondary bacterial infection in inflammatory cases 3
• Delaying systemic antifungal therapy when kerion is present 1
• Discontinuing antifungal therapy when dermatophytid reactions occur (these represent cell-mediated host response to dying dermatophytes and should be treated symptomatically with topical corticosteroids) 1
• Using griseofulvin as first-line treatment for non-Microsporum infections, as it requires longer treatment duration and has lower cure rates than terbinafine 2