What antifungal medication can be prescribed for a child's foot fungal infection?

Topical Terbinafine for Pediatric Tinea Pedis

For a child's foot fungal infection (tinea pedis/athlete's foot), prescribe topical terbinafine 1% cream applied once daily for 1 week, which provides superior efficacy and faster cure compared to other topical antifungals. 1

First-Line Treatment Recommendation

• Terbinafine 1% cream applied once daily for 1 week is the optimal topical treatment for tinea pedis in children, offering the advantage of short treatment duration with high cure rates 1
• This regimen is FDA-approved for pediatric use and specifically indicated for athlete's foot 2
• Terbinafine demonstrates fungicidal (not just fungistatic) activity against the most common causative organisms: T. rubrum and T. mentagrophytes 1

Evidence Supporting Terbinafine Superiority

• In pediatric studies, terbinafine 1% cream achieved 92% efficacy (complete clinical and mycological cure) when applied once daily for just 1 week in children ages 2-15 years 3
• Comparative trials show terbinafine 1% cream for 1 week achieves 93.5% mycological cure versus 73.1% with clotrimazole 1% cream for 4 weeks (p=0.0001), demonstrating both superior efficacy and shorter treatment duration 4
• The Pediatrics guideline confirms ciclopirox olamine 0.77% cream applied twice daily for 4 weeks achieves approximately 60% cure rates, which is inferior to terbinafine's performance 1

Alternative Topical Options

If terbinafine is unavailable or contraindicated:

• Ciclopirox olamine 0.77% cream or gel applied twice daily for 4 weeks provides broad-spectrum coverage against dermatophytes 1
• Clotrimazole 1% cream applied twice daily for 4 weeks is an over-the-counter alternative, though less effective than terbinafine 1, 4
• Miconazole 2% powder or cream can be used for mild cases, particularly helpful for moisture absorption 5

When to Consider Oral Therapy

Oral antifungals should be considered in specific circumstances:

• Extensive disease involving large areas of the foot 6
• Moccasin-type tinea pedis (chronic, dry, hyperkeratotic infection of the plantar surface) 6, 7
• Failed topical treatment after appropriate duration 6
• Immunocompromised patients 6

For these cases, oral terbinafine 250 mg once daily for 1 week demonstrates similar efficacy to 4 weeks of topical clotrimazole but with faster clinical resolution 1

Pediatric Dosing for Oral Terbinafine (if needed)

Weight-based dosing for children requiring systemic therapy:

• <20 kg: 62.5 mg daily 1
• 20-40 kg: 125 mg daily 1
• >40 kg: 250 mg daily 1
• Duration: 6 weeks for fingernails, 12 weeks for toenails if onychomycosis is present 1

Critical Prevention Measures

• Thorough drying between toes after bathing is essential, as moisture promotes fungal growth 1
• Daily sock changes and periodic cleaning of athletic footwear reduce recurrence 1
• Foot powder application after bathing has been shown to reduce tinea pedis rates from 8.5% to 2.1%, primarily by reducing T. mentagrophytes 1
• Examine for concurrent tinea infections at other sites (tinea corporis, tinea cruris) as these can serve as reinfection sources 1

Important Clinical Pitfalls

• Always confirm diagnosis mycologically (KOH preparation or culture) before treating, as many conditions mimic tinea pedis including eczema and contact dermatitis 6
• Screen family members for tinea pedis, as household transmission is common and can lead to treatment failure 1
• Obesity and diabetes are risk factors for tinea pedis and may require more aggressive treatment 1
• Covering active foot lesions with socks before wearing undershorts prevents spread to the groin (tinea cruris) 1
• Terbinafine is generally well-tolerated, but rare serious adverse events include neutropenia and liver failure (typically in those with preexisting liver disease) 1

Practical Application Algorithm

1. Confirm diagnosis with KOH preparation or culture if presentation is atypical
2. Assess extent: localized interdigital vs. extensive/moccasin-type
3. For localized disease: Terbinafine 1% cream once daily × 1 week
4. For extensive/moccasin disease: Consider oral terbinafine (weight-based dosing)
5. Implement prevention: foot hygiene education, daily sock changes, foot powder
6. Screen household contacts and treat if infected
7. Follow-up at 2-4 weeks to confirm mycological cure