What is the appropriate treatment for tinea pedis (athlete’s foot)?

Treatment of Tinea Pedis

First-Line Topical Therapy

Topical terbinafine 1% cream applied twice daily for 1 week is the most effective first-line treatment for interdigital tinea pedis, offering superior efficacy with the shortest treatment duration compared to all other topical antifungals. 1, 2

• For interdigital tinea pedis (between the toes): Apply terbinafine 1% cream twice daily (morning and night) for 1 week. 3
• For plantar tinea pedis (bottom or sides of the foot): Apply terbinafine 1% cream twice daily for 2 weeks. 3
• Terbinafine's fungicidal action allows for dramatically shorter treatment courses than fungistatic agents like azoles. 4, 5
• Meta-analysis of 2,899 patients demonstrates terbinafine achieves 66-78% effective cure rates with just 1 week of therapy. 2, 4

Alternative Topical Agents

• Ciclopirox olamine 0.77% cream/gel applied twice daily for 4 weeks achieves approximately 60% cure at end of treatment and 85% cure two weeks post-treatment, making it superior to clotrimazole. 1, 2
• Clotrimazole 1% cream applied twice daily for 4 weeks is less effective than both terbinafine and ciclopirox but remains widely available over-the-counter. 1, 2
• Terbinafine 1% cream for 1 week is significantly superior to clotrimazole 1% cream for 4 weeks in head-to-head trials. 5

Oral Therapy for Severe or Resistant Cases

Reserve oral antifungals for severe disease, failed topical therapy, concomitant onychomycosis, or immunocompromised patients. 1, 2

First-Line Oral Agent

• Terbinafine 250 mg once daily for 1-2 weeks is the most effective oral treatment, with fungicidal action and >70% oral absorption unaffected by food. 1
• Oral terbinafine provides similar mycological efficacy to 4 weeks of topical clotrimazole but with faster clinical resolution. 1, 2
• Terbinafine has lower minimum inhibitory concentration (MIC) against dermatophytes than itraconazole, making it the preferred systemic agent. 1

Alternative Oral Agents

• Itraconazole 100 mg daily for 2 weeks offers comparable efficacy to terbinafine but with slightly higher relapse rates. 1, 2
• Pulse dosing of itraconazole 200-400 mg per day for 1 week per month is an alternative regimen. 1
• Fluconazole is less effective than both terbinafine and itraconazole for dermatophyte infections but may be useful when other agents are contraindicated due to fewer drug interactions. 1
• Griseofulvin is not recommended as first-line therapy due to lower efficacy (30-40% cure rates) and longer treatment duration. 1

Critical Prevention Measures to Prevent Recurrence

Failing to address contaminated footwear and untreated family members are the two most common causes of treatment failure and recurrence. 1

Footwear Decontamination

• Discard old, moldy footwear when possible because shoes harbor large numbers of viable dermatophyte spores. 1
• If shoes cannot be discarded, place naphthalene mothballs inside shoes, seal in a plastic bag for minimum 3 days, then air out to decontaminate. 1
• Spray terbinafine solution inside shoes periodically for additional antifungal protection. 1
• Apply antifungal powders containing miconazole, clotrimazole, or tolnaftate inside shoes. 1

Daily Hygiene Practices

• Thoroughly dry between toes after showering to reduce moisture that promotes fungal growth. 1, 2
• Change to cotton, absorbent socks daily, which reduces infection rates from 8.5% to 2.1%. 1, 2
• Apply antifungal foot powder after bathing for additional prevention. 1, 2
• Wear protective footwear in public bathing facilities, gyms, and hotel rooms. 1

Household Management

• Treat all infected family members simultaneously to prevent reinfection cycles. 1, 2
• Avoid sharing toenail clippers with family members. 1
• Cover active foot lesions with socks before wearing underwear to prevent spread to groin area (tinea cruris). 1, 2

Special Considerations and Monitoring

Concomitant Onychomycosis

• Always examine for nail involvement because onychomycosis requires extended oral terbinafine therapy (12-16 weeks) and serves as a reservoir for reinfection. 1
• Up to one-third of diabetic patients have onychomycosis, which significantly predicts foot ulcer development. 1

Safety Monitoring for Oral Terbinafine

• Obtain baseline liver function tests (LFTs) and complete blood count (CBC) before initiating oral terbinafine in adults with history of hepatotoxicity or hematologic abnormalities. 1
• Monitor for rare but serious adverse events including isolated neutropenia and hepatic failure, particularly in patients with pre-existing liver disease. 1, 2
• Common adverse effects include headache, taste disturbance, and gastrointestinal upset. 1

High-Risk Populations

• Diabetic patients should receive terbinafine over itraconazole due to lower risk of drug interactions and hypoglycemia. 1
• Risk factors for tinea pedis include swimming, running, warm humid environments, male gender, obesity, and diabetes. 1, 2

Athletes and Return to Play

• Athletes require minimum 72 hours of topical or systemic antifungal therapy before return to contact sports. 1
• Cover lesions with gas-permeable dressing followed by underwrap and stretch tape. 1
• Exclude from swimming pools and discourage barefoot walking in locker rooms until treatment initiated. 1

Treatment Endpoint

The definitive endpoint for adequate treatment should be mycological cure, not just clinical response. 2

• Consider follow-up with repeat mycology sampling at the end of the standard treatment period to confirm eradication. 2
• Continue treatment for at least one week after clinical clearing of infection. 6