What is the drug of choice for treating tinea capitis, particularly in children?

Drug of Choice for Tinea Capitis

Oral griseofulvin 15-20 mg/kg/day for 6-8 weeks is the first-line treatment for tinea capitis, though terbinafine offers a shorter 2-4 week treatment duration and should be selected based on the causative organism. 1

Mandatory Oral Therapy Requirement

• Oral antifungal therapy is absolutely required for tinea capitis—topical therapy alone is completely ineffective and should never be used as monotherapy. 1, 2
• The infection involves the hair shaft, which cannot be reached by topical agents alone. 2

Organism-Directed Treatment Selection

The choice between griseofulvin and terbinafine depends critically on the causative organism:

For Trichophyton Species (Most Common in North America)

• Terbinafine is the preferred agent for Trichophyton infections due to superior fungicidal activity and shorter treatment duration. 2
• Dosing: <20 kg: 62.5 mg/day; 20-40 kg: 125 mg/day; >40 kg: 250 mg/day for 2-4 weeks 1
• Gastrointestinal disturbances and rashes occur in less than 8% of children 2

For Microsporum Species

• Griseofulvin is the preferred agent for Microsporum infections, as terbinafine is relatively ineffective against this organism. 1, 2
• Terbinafine fails against Microsporum because it cannot be incorporated into hair shafts in prepubertal children and doesn't reach the scalp surface where arthroconidia are located 2
• Dosing: 15-20 mg/kg/day for patients <50 kg, or 1 g/day for patients >50 kg, continued for 6-8 weeks 1
• Eight weeks of griseofulvin is significantly more effective than 4 weeks of terbinafine for confirmed Microsporum infection 2

When to Start Treatment Empirically

• Begin treatment before mycology results if cardinal clinical signs are present: scale, lymphadenopathy, alopecia, or kerion. 2
• Collect specimens via scalp scrapings, hair pluck, brush, or swab for microscopy and culture to guide definitive therapy 1, 2

Critical Treatment Endpoint

• The definitive endpoint is mycological cure, not just clinical improvement—repeat mycology sampling is mandatory until clearance is achieved. 2
• If clinical improvement occurs but mycology remains positive, continue current therapy for an additional 2-4 weeks 1

Second-Line Options for Treatment Failure

If initial therapy fails, assess these factors:

• Poor compliance with medication regimen 1, 2
• Suboptimal drug absorption 1
• Organism insensitivity to the chosen agent 1
• Reinfection from untreated contacts or contaminated fomites 1

For treatment failure with no clinical improvement, switch to second-line therapy:

• Itraconazole 5 mg/kg/day for 2-4 weeks (effective against both Trichophyton and Microsporum species) 2
• Fluconazole as an alternative for refractory cases, with favorable tolerability and liquid formulation available 2
• Switch between terbinafine and griseofulvin based on organism identification 1

Essential Adjunctive Measures

• Use topical antifungal shampoos (selenium sulfide or ketoconazole) as adjunctive therapy only, never as monotherapy. 2
• Screen and treat all family members and close contacts, especially for T. tonsurans infections, as over 50% of household contacts may be affected. 1, 2
• Clean all fomites (hairbrushes, combs, towels) with disinfectant or 2% sodium hypochlorite solution 1, 2

Important Contraindications and Caveats

• Griseofulvin is contraindicated in lupus erythematosus, porphyria, and severe liver disease 1
• Never use terbinafine for Microsporum infections due to poor efficacy 2
• Avoid underdosing griseofulvin—higher doses (15-20 mg/kg/day) are needed due to increasing treatment failures with lower doses 2

School Attendance

• Children receiving appropriate systemic and adjunctive topical therapy should be allowed to attend school or nursery—exclusion is impractical and unnecessary. 1, 2