What is the best treatment for a two-year-old with onychomycosis (fungal infection of the toenail)?

Treatment of Fungal Toenail Infection in a Two-Year-Old Child

For a two-year-old child with onychomycosis (fungal toenail infection), oral terbinafine is the first-line treatment, dosed at 62.5 mg daily if weight is <20 kg for 12 weeks for toenail infection. 1

First-Line Treatment Options

Systemic Therapy

Systemic antifungal therapy is generally recommended for pediatric onychomycosis due to higher cure rates compared to topical therapy alone:

1. Terbinafine (First-line)

   • Dosing: 62.5 mg daily if weight <20 kg, 125 mg daily for 20-40 kg weight 1
   • Duration: 12 weeks for toenail infection
   • Advantages: Highest efficacy against dermatophytes, fungicidal action
   • Monitoring: Baseline liver function tests and complete blood count recommended

2. Itraconazole (First-line alternative)

   • Dosing: 5 mg/kg/day for 1 week per month ("pulse therapy") 1
   • Duration: Three pulses for toenail infection
   • Administration: Optimally absorbed with food and acidic pH
   • Monitoring: Hepatic function tests recommended with pre-existing liver issues

Second-Line Options

If first-line treatments are contraindicated or not tolerated:

1. Fluconazole

   • Dosing: 3-6 mg/kg once weekly 1
   • Duration: 18-26 weeks for toenail infection
   • Monitoring: Baseline liver function tests and full blood count

2. Griseofulvin

   • Dosing: 10 mg/kg per day 1
   • Note: Lower efficacy, longer treatment duration, and higher relapse rates make this less desirable

Topical Therapy Considerations

While topical monotherapy is generally less effective for onychomycosis, it may be considered in very mild cases or as adjunctive therapy:

• Ciclopirox 8% nail lacquer: Applied once daily for up to 48 weeks for toenails 2
• Amorolfine 5% lacquer: Applied once or twice weekly for 6-12 months 1
• Efinaconazole 10% solution: Recently approved for children ≥6 years with promising results (mycological cure rate of 65%) 3

Treatment Algorithm

1. Confirm diagnosis through clinical examination and, if possible, fungal culture or KOH preparation

2. Assess severity:

   • Mild/superficial: Consider topical therapy
   • Moderate to severe: Proceed with systemic therapy

3. Treatment selection:

   • First choice: Terbinafine oral therapy (weight-based dosing)
   • If Candida is suspected: Consider itraconazole (better activity against Candida)
   • If systemic therapy contraindicated: Use topical ciclopirox or amorolfine

4. Adjunctive measures:

   • Gentle nail debridement/filing of affected areas
   • Treatment of concomitant tinea pedis if present
   • Examination of family members for potential sources of infection

Important Considerations

• Children generally respond better and faster to treatment than adults, with higher cure rates 1
• Pediatric onychomycosis is less common than in adults (<0.5% prevalence) but is increasingly recognized 4
• Always check for concomitant tinea pedis and examine family members, as familial disease often occurs 1
• Combination of topical and systemic therapy may provide synergistic effects and improved outcomes 1
• Recurrence prevention is important - consider periodic application of topical antifungals to prevent reinfection 5

Pitfalls to Avoid

• Failing to confirm diagnosis before starting treatment
• Inadequate treatment duration leading to relapse
• Not addressing potential sources of reinfection in the household
• Overlooking the need for baseline laboratory monitoring with systemic therapy
• Underestimating the importance of adherence to the full treatment course