What are the drugs of choice for treating tinea pedis (athlete's foot)?

Drugs of Choice for Tinea Pedis (Athlete's Foot)

Terbinafine is the first-line treatment for tinea pedis, with topical 1% cream applied twice daily for 1 week between the toes or 2 weeks on the bottom/sides of the foot providing superior efficacy compared to other antifungals. 1, 2

First-Line Topical Treatments

Terbinafine (Allylamine)

• Mechanism: Fungicidal action against dermatophytes
• Dosing: 1% cream applied twice daily 1
  • Between toes: 1 week
  • Bottom/sides of foot: 2 weeks
• Efficacy: Superior to clotrimazole with 93.5% mycological cure rate after just 1 week (vs. 73.1% for 4 weeks of clotrimazole) 3
• Advantages: Shorter treatment duration due to fungicidal properties 4
• Novel formulation: Film-forming solution (FFS) allows for single-dose treatment with 66% effective treatment rate 5

Ciclopirox Olamine

• Dosing: 0.77% cream/gel applied twice daily for 4 weeks 2, 6
• Efficacy: ~60% clinical and mycological cure at end of treatment, 85% cure two weeks post-treatment 2
• Spectrum: Effective against Trichophyton rubrum, T. mentagrophytes, and Epidermophyton floccosum 2

Other Topical Options

• Clotrimazole: 1% cream applied twice daily for 4 weeks (less effective than terbinafine) 3
• Miconazole, tolnaftate: Used in antifungal powders for prevention and treatment 2

Oral Antifungal Therapy

Oral therapy should be reserved for:

• Severe or extensive disease
• Failed topical therapy
• Immunocompromised patients
• Concomitant onychomycosis 7

Oral Options (in order of preference)

1. Terbinafine: 250 mg daily for 1 week; faster clinical resolution than topicals 2

   • Well-tolerated but monitor for rare hepatotoxicity or neutropenia 2

2. Itraconazole: 100 mg daily for 2 weeks 2

   • Similar mycological efficacy to terbinafine but slightly higher relapse rate 2

3. Fluconazole: Alternative for patients unable to tolerate terbinafine or itraconazole 2

Treatment Algorithm

1. Uncomplicated tinea pedis (interdigital or mild moccasin type):

   • Start with topical terbinafine 1% cream twice daily (1-2 weeks)
   • If no improvement after 2 weeks, consider switching to ciclopirox 0.77%

2. Severe, extensive, or treatment-resistant tinea pedis:

   • Oral terbinafine 250 mg daily for 1 week
   • Alternative: oral itraconazole 100 mg daily for 2 weeks

3. Prevention of recurrence:

   • Apply antifungal powders containing miconazole, clotrimazole, or tolnaftate to shoes and feet 2
   • Wear cotton, absorbent socks and change daily 2
   • Thoroughly dry between toes after bathing 2
   • Clean athletic footwear periodically 2

Important Considerations

• Causative organisms: Most commonly Trichophyton rubrum and T. mentagrophytes 2, 7
• Risk factors: Male gender, athletes (especially swimmers and runners), obesity, diabetes 2
• Diagnosis: Clinical features plus KOH preparation of skin scrapings from active border 7
• Prevention: For athletes or those in communal settings, foot powder after bathing reduced infection rates from 8.5% to 2.1% in one study 2

Common Pitfalls

1. Inadequate treatment duration: Even with fungicidal agents like terbinafine, premature discontinuation can lead to recurrence
2. Neglecting environmental factors: Failure to address contaminated footwear can lead to reinfection 2
3. Missing concomitant infections: Tinea pedis can spread to cause tinea cruris; consider covering foot lesions with socks before wearing underwear 2
4. Overlooking family members: All infected family members should be treated simultaneously as the infection is contagious 2

For severe or recalcitrant cases, consider discarding heavily contaminated footwear or decontaminating with naphthalene mothballs in a sealed plastic bag for 3 days 2.