What is the recommended treatment for pediatric patients with scalp ringworm (tinea capitis)?

Treatment of Scalp Ringworm (Tinea Capitis) in Pediatric Patients

Oral antifungal therapy is mandatory for tinea capitis in children, with terbinafine as first-line for Trichophyton species (2-4 weeks) and griseofulvin for Microsporum species (6-8 weeks), based on organism identification. 1, 2

Diagnostic Approach Before Treatment

• Collect scalp samples via scrapings, hair pluck, brush, or swab for microscopy and culture to identify the causative organism 1, 2
• Treatment can be initiated empirically before mycology results if cardinal clinical signs are present: scale, lymphadenopathy, alopecia, or kerion 1, 2
• Microscopy using potassium hydroxide provides rapid preliminary diagnosis while awaiting culture results 2

First-Line Treatment Selection Algorithm

For Trichophyton Species (T. tonsurans, T. violaceum, T. soudanense):

Terbinafine is the preferred first-line agent due to fungicidal activity and superior efficacy 1, 2

• <20 kg: 62.5 mg/day for 2-4 weeks 1
• 20-40 kg: 125 mg/day for 2-4 weeks 1
• >40 kg: 250 mg/day for 2-4 weeks 1
• Advantages include shorter treatment duration (improving compliance) and gastrointestinal disturbances or rashes in <8% of children 1, 2

For Microsporum Species (M. canis, M. audouinii):

Griseofulvin is the preferred first-line agent with 88.5% response rate for Microsporum 1, 2

• <50 kg: 15-20 mg/kg/day (single or divided dose) for 6-8 weeks 1, 3
• >50 kg: 1 g/day (single or divided dose) for 6-8 weeks 1, 3
• Griseofulvin remains the only licensed treatment for tinea capitis in children in the UK 1
• Eight weeks of griseofulvin is significantly more effective than 4 weeks of terbinafine for confirmed Microsporum infection 2

Critical Treatment Principle

Terbinafine fails against Microsporum species (67.9% response rate) because it cannot be incorporated into hair shafts in prepubertal children and doesn't reach the scalp surface where arthroconidia are located 1, 2

Second-Line Treatment Options

Itraconazole:

• 5 mg/kg/day for 2-4 weeks or 50-100 mg/day for 4 weeks 1, 2
• Effective against both Trichophyton and Microsporum species 1, 2
• Important drug interactions: enhanced toxicity with warfarin, certain antihistamines, antipsychotics, midazolam, digoxin, and simvastatin 4

Fluconazole:

• Third-line option with favorable tolerability profile and availability in liquid form 2, 5
• Not licensed for tinea in children under 10 years in the UK 4

Management of Treatment Failure

• Consider poor compliance, suboptimal drug absorption, organism insensitivity, or reinfection 1, 2
• If clinical improvement but positive mycology persists: Continue current therapy for additional 2-4 weeks 1, 2
• If no clinical improvement: Switch to second-line therapy 1, 2
• For griseofulvin failure with Trichophyton: Switch to terbinafine 1
• For terbinafine failure with Microsporum: Switch to griseofulvin 1

Adjunctive Measures

• Topical antifungal therapy should be used as adjunctive treatment only; topical therapy alone is never adequate 2, 3
• Screen all family members and close contacts for T. tonsurans cases, as over 50% may be affected 2, 4
• Clean contaminated combs and brushes with disinfectant or 2% sodium hypochlorite solution 2, 4
• Children receiving appropriate systemic therapy can attend school or nursery; exclusion is unnecessary 2

Monitoring and Follow-Up

• The definitive endpoint is mycological cure, not clinical improvement 1, 2
• Repeat mycology sampling is mandatory until clearance is documented 1, 2
• Monitor for treatment side effects, though serious adverse events are rare with recommended durations 1

Common Pitfalls to Avoid

• Never use topical therapy alone as monotherapy—it cannot eradicate scalp infections 2, 3
• Avoid underdosing griseofulvin; higher doses (15-20 mg/kg/day) are needed due to increasing treatment failures with lower doses 2, 5
• Do not use terbinafine for Microsporum infections due to poor efficacy 2
• Do not stop treatment based on clinical improvement alone; continue until mycological clearance is confirmed 1, 2