What is the recommended treatment for a pediatric patient with a fungal infection in the toe?

Treatment of Pediatric Fungal Toe Infections

For a pediatric patient with a fungal infection of the toe (tinea pedis), topical terbinafine 1% cream applied twice daily for 1 week is the first-line treatment, with systemic therapy reserved for severe, extensive, or treatment-resistant cases. 1

Diagnostic Confirmation

Before initiating treatment, obtain mycological confirmation through potassium hydroxide (KOH) preparation with microscopy and/or fungal culture to avoid treating non-fungal conditions. 2 The causative organisms are predominantly T. rubrum and T. mentagrophytes. 1

Examine the entire child and family unit for concomitant infections, as dermatophyte organisms can spread to multiple body sites and family transmission is common. 2, 3 Check specifically for:

• Tinea capitis (scalp infection) 2
• Nail involvement (onychomycosis) 2
• Infections in parents and siblings 3

First-Line Topical Treatment

Topical terbinafine 1% cream applied twice daily for 1 week is the most effective topical regimen, achieving mycological cure rates of 93.5% compared to 73.1% with clotrimazole after 4 weeks of treatment. 4 This short-duration therapy is possible because terbinafine has fungicidal (not just fungistatic) activity against dermatophytes. 5, 6

Alternative Topical Options

• Ciclopirox olamine 0.77% cream/gel achieves approximately 60% clinical and mycological cure at end of treatment, increasing to 85% two weeks post-treatment 1
• Clotrimazole 1% cream is less effective than terbinafine but widely available over-the-counter 1

Systemic Therapy Indications

Reserve oral antifungals for:

• Severe or extensive disease 1
• Failed topical therapy 1
• Concomitant onychomycosis (nail involvement) 1
• Immunocompromised patients 1

Oral Treatment Options

Terbinafine is the preferred systemic agent due to superior efficacy and safety profile in children. 2, 3

Weight-based dosing for terbinafine: 2, 3

• <20 kg: 62.5 mg daily
• 20-40 kg: 125 mg daily

• 40 kg: 250 mg daily

Duration: 1-2 weeks for tinea pedis (extended from the typical 1-week course for more extensive infections) 1

Terbinafine is unlicensed for pediatric use, requiring baseline liver function tests and complete blood count before initiation. 3 However, it has been shown to be effective and safe in multiple pediatric studies. 7

Alternative Systemic Options

Itraconazole offers flexible dosing with pulse regimens of 5 mg/kg per day for 1 week each month, though it has slightly lower efficacy than terbinafine. 2, 1

Fluconazole is a second-line option when terbinafine and itraconazole are contraindicated or not tolerated, dosed at 3-6 mg/kg once weekly. 2, 3 Fluconazole appears less effective than itraconazole or terbinafine for dermatophyte infections but has fewer drug interactions. 1

Griseofulvin (10 mg/kg per day) is the only antifungal licensed for children over 1 month with fungal infections, but it is no longer first-line due to lower efficacy (30-40% cure rates) and longer treatment duration. 8, 1 It should only be used when other drugs are unavailable or contraindicated. 8

Concurrent Management Strategies

Always combine systemic treatment with topical antifungal therapy for the foot infection when treating nail involvement. 2 This dual approach addresses both sites of infection simultaneously.

Implement prevention measures concurrently: 1, 2

• Apply antifungal powders (miconazole, clotrimazole, or tolnaftate) inside shoes regularly
• Decontaminate or replace contaminated footwear (place naphthalene mothballs in shoes and seal in plastic bag for minimum 3 days)
• Change socks daily and wear cotton, absorbent socks
• Keep nails short and clean
• Avoid sharing nail clippers with infected family members
• Treat all infected family members simultaneously to prevent reinfection

Critical Pitfalls to Avoid

Failing to treat all infected family members simultaneously results in reinfection. 1 Examine and treat parents and siblings as needed. 2, 3

Neglecting contaminated footwear as a source of reinfection leads to recurrence, as shoes can contain large numbers of infective fungal elements. 1

Not examining for concomitant nail involvement misses onychomycosis, which requires longer systemic therapy (12 weeks for toenails). 2, 3

Special Considerations for Athletes

Athletes require a minimum of 72 hours of topical or systemic antifungal therapy before return to contact sports, with lesions covered appropriately. 1 Exclude from swimming pools and discourage barefoot walking in locker rooms until treatment is initiated. 1

Monitoring

Children achieve higher cure rates and faster response than adults due to thinner nail plates and faster nail growth when nails are involved. 3 However, monitor for at least 48 weeks from treatment start to identify potential relapse when treating onychomycosis. 2, 3