Treatment of Fungal Toenail Infection in Children

First-Line Systemic Treatment

The British Journal of Dermatology recommends oral terbinafine as the first-line treatment for fungal toenail infection in children, with a weight-based dose of 62.5 mg daily if weight <20 kg, or 125 mg daily if weight 20-40 kg, given for 12 weeks for toenails 1
Terbinafine is generally preferred over itraconazole for dermatophyte onychomycosis in children due to its fungicidal activity and efficacy, with a strength of recommendation of 1 1
The dosage of terbinafine is 62.5 mg daily if weight <20 kg, and 125 mg daily if weight 20-40 kg, with a duration of 12 weeks for toenail infection 1
Terbinafine should be taken with food to optimize absorption 1

Baseline liver function tests and complete blood count should be obtained before starting terbinafine treatment, as it is unlicensed for use in children and may cause hepatic impairment 1
Terbinafine is contraindicated in hepatic impairment 1

Common adverse effects of terbinafine include headache, taste disturbance, and gastrointestinal upset 1
Terbinafine can also aggravate psoriasis and cause subacute lupus-like syndrome 1

If terbinafine is contraindicated or not tolerated, itraconazole may be used as a second-line treatment, with a pulse therapy regimen of 5 mg/kg/day for 1 week per month, for a total of 3 months 1
Itraconazole should be taken with food and acidic pH for optimal absorption, and hepatic function tests should be monitored in patients with pre-existing abnormalities or when using continuous therapy >1 month 1
Itraconazole is contraindicated in heart failure and hepatotoxicity 1

Topical antifungals may be considered for superficial or early distal infection with <80% nail plate involvement and no lunula involvement, or when systemic therapy is contraindicated 2
Amorolfine 5% lacquer may be applied once or twice weekly for 6-12 months 3

Treatment duration for fungal toenail infection is prolonged, with a minimum of 12 weeks for toenails with systemic therapy, and up to 18 months may be required for complete nail clearance 4
Preventive measures, such as wearing protective footwear in public areas, treating tinea pedis promptly, keeping nails short, and treating all infected family members simultaneously, are essential to prevent recurrence 4

If the infection is actually a bacterial paronychia rather than fungal onychomycosis, warm water soaks and topical antibiotics may be used for mild cases, while oral antibiotics (e.g., cephalexin, amoxicillin-clavulanate) may be used for moderate to severe infections 1, 2
Incision and drainage may be necessary if an abscess is present 1