What is the recommended treatment for tinea (ringworm) of the scalp?

Treatment of Tinea Capitis

Oral systemic antifungal therapy is mandatory for tinea capitis, and the choice of agent depends on the causative organism: terbinafine for Trichophyton species (2-4 weeks) and griseofulvin for Microsporum species (6-8 weeks). 1

Diagnostic Confirmation Before Treatment

• Collect scalp samples via scrapings, hair pluck, brush, or swab for microscopy and culture to identify the causative organism 1
• Potassium hydroxide (KOH) preparation provides rapid preliminary diagnosis 1, 2
• Start empirical treatment immediately if cardinal clinical signs are present (scale, lymphadenopathy, alopecia, or kerion) without waiting for culture results 1

First-Line Treatment Algorithm

For Trichophyton Species Infections

Terbinafine is the preferred agent due to fungicidal activity and superior efficacy with shorter treatment duration 1:

• Children <20 kg: 62.5 mg/day for 2-4 weeks 1
• Children 20-40 kg: 125 mg/day for 2-4 weeks 1
• Children >40 kg and adults: 250 mg/day for 2-4 weeks 1
• Gastrointestinal disturbances and rashes occur in <8% of children 1
• The shorter duration (2-4 weeks vs 6-8 weeks) significantly improves compliance 1

For Microsporum Species Infections

Griseofulvin is the only effective first-line agent for Microsporum infections 1:

• Children <50 kg: 15-20 mg/kg/day for 6-8 weeks 1, 2
• Children >50 kg and adults: 1 g/day for 6-8 weeks 1, 2
• Critical pitfall: 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 1
• Eight weeks of griseofulvin is significantly more effective than 4 weeks of terbinafine for confirmed Microsporum infection 1

Second-Line Options for Treatment Failure

If initial therapy fails, consider these factors: poor compliance, suboptimal drug absorption, organism insensitivity, or reinfection 1

Management algorithm for treatment failure 1:

• If clinical improvement but positive mycology persists: Continue current therapy for additional 2-4 weeks
• If no clinical improvement: Switch to second-line therapy

Second-Line Agents

• Itraconazole: 5 mg/kg/day for 2-4 weeks or 50-100 mg/day for 4 weeks, effective against both Trichophyton and Microsporum species 1
• Fluconazole: Alternative for refractory cases with favorable tolerability profile and availability in liquid form 1

Adjunctive Measures

• Topical antifungal shampoos (selenium sulfide or ketoconazole) as adjunctive therapy to reduce spore transmission 1
• Screen and treat family members and close contacts, especially for T. tonsurans infections which spread easily 1

Monitoring and Treatment Endpoint

• Treatment endpoint is mycological cure, not just clinical improvement 1
• Repeat mycology sampling until clearance is achieved 1
• Monitor for treatment side effects, though liver enzyme monitoring is generally unnecessary if therapy is limited to ≤4 weeks 3

Critical Pitfalls to Avoid

• Never use terbinafine for Microsporum infections due to poor efficacy 1
• Never rely on topical therapy alone as it cannot eradicate scalp infections 1
• Avoid underdosing griseofulvin—higher doses (20-25 mg/kg/day) are needed due to increasing treatment failures with lower doses 1, 3
• Do not discontinue therapy prematurely—clinical relapse will occur if medication is not continued until the infecting organism is completely eradicated 2