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

Treatment of Tinea Capitis

Oral antifungal therapy is mandatory for tinea capitis, with the choice between griseofulvin and terbinafine determined by the causative organism: use terbinafine for Trichophyton species and griseofulvin for Microsporum species. 1

Diagnostic Confirmation Before Treatment

• Obtain scalp samples via scrapings, hair pluck, brush, or swab for microscopy and culture to identify the causative dermatophyte 1, 2
• Potassium hydroxide (KOH) preparation provides rapid preliminary diagnosis while awaiting culture results 2, 3
• Begin empiric treatment when cardinal signs are present (scaling, lymphadenopathy, alopecia, or kerion) without waiting for culture confirmation 1

First-Line Treatment Algorithm

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

Terbinafine is superior for Trichophyton infections due to its fungicidal mechanism and higher efficacy against these organisms 1:

• < 20 kg: 62.5 mg daily for 2-4 weeks 1, 2
• 20-40 kg: 125 mg daily for 2-4 weeks 1, 2
• > 40 kg: 250 mg daily for 2-4 weeks 1, 2

The shorter treatment duration (2-4 weeks) improves compliance compared to griseofulvin 1. Terbinafine is well-tolerated with gastrointestinal disturbances and rashes occurring in <8% of children, with only 0.8% requiring discontinuation 1.

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

Griseofulvin is significantly more effective for Microsporum infections, requiring 8 weeks of treatment 1:

• < 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 many countries, including the UK 1, 3. The suspension formulation allows more accurate dosing in children, though it is more expensive and requires prolonged treatment 1.

Critical caveat: Terbinafine fails against Microsporum because it is not excreted in sweat or sebum of prepubertal children and cannot be incorporated into the hair shaft, preventing it from reaching the scalp surface where Microsporum arthroconidia are located 1.

When Organism is Unknown

• Start treatment based on local epidemiology: In North America where T. tonsurans predominates, initiate terbinafine; in regions where M. canis is common, start griseofulvin 1, 4
• Adjust therapy once culture results identify the specific organism 1

Second-Line Treatment

For Treatment Failures

First assess for non-compliance, suboptimal drug absorption, relative organism insensitivity, or reinfection 1, 5:

• If clinical improvement with ongoing positive cultures: Continue current therapy for an additional 2-4 weeks 1, 5
• If no initial clinical improvement: Switch to second-line therapy 1

Itraconazole is the preferred second-line agent, effective against both Trichophyton and Microsporum species 1, 2:

• 5 mg/kg/day for 2-4 weeks or 50-100 mg/day for 4 weeks 2

Fluconazole is an alternative for refractory cases, particularly useful in younger children due to liquid formulation and favorable tolerability 2, 6.

Adjunctive Measures

• Topical therapy alone is inadequate and not recommended as monotherapy 1, 3
• Use sporicidal shampoos (2% ketoconazole or 1% selenium sulfide) as adjunctive treatment to reduce spore transmission and aid scale removal 6, 4
• Screen and treat family members and close contacts, especially for T. tonsurans infections which are highly contagious 2

Monitoring and Treatment Endpoint

• The treatment endpoint is mycological cure, not merely clinical improvement 2
• Repeat mycology sampling until clearance is achieved 2
• Monitor for adverse effects, though liver enzyme monitoring is generally unnecessary for treatment courses ≤4 weeks 6

Important Contraindications and Drug Interactions

Griseofulvin contraindications: Lupus erythematosus, porphyria, severe liver disease 1

Griseofulvin drug interactions: Plasma concentration decreased by rifampicin and increased by cimetidine 1

Common Pitfalls to Avoid

• Never use topical therapy alone—oral antifungals are essential for penetrating the hair shaft 1, 3
• Do not use terbinafine for Microsporum infections—it will fail due to inadequate drug delivery to the scalp surface in children 1
• Do not use standard 4-week griseofulvin courses for Microsporum—8 weeks is required for adequate efficacy 1
• Avoid premature discontinuation based on clinical improvement alone—continue until mycological cure is documented 2, 3