What is the first line of treatment for tinea (ringworm) infections?

First-Line Treatment for Tinea Infections

Treatment Selection Based on Site of Infection

For tinea capitis (scalp ringworm), oral griseofulvin 15-20 mg/kg/day for 6-8 weeks is the first-line treatment and remains the only licensed option for children in the UK, though terbinafine offers shorter treatment duration (2-4 weeks) which may improve compliance. 1, 2

For tinea corporis (body) and tinea cruris (groin), topical antifungal therapy is first-line treatment for localized disease, while oral therapy is reserved for extensive infections, treatment failures, or immunocompromised patients. 3, 4, 5

For tinea pedis (foot), topical therapy applied for 4 weeks with azoles or 1-2 weeks with allylamines is first-line, with oral therapy reserved for resistant or extensive cases. 4, 5

Specific Treatment Recommendations by Body Site

Tinea Capitis (Scalp)

• Oral therapy is mandatory; topical therapy alone is not effective 1, 2
• Griseofulvin dosing: 15-20 mg/kg/day (single or divided dose) for patients <50 kg, or 1 g/day for patients >50 kg, continued for 6-8 weeks 1
• Terbinafine alternative dosing: <20 kg: 62.5 mg/day; 20-40 kg: 125 mg/day; >40 kg: 250 mg/day for 2-4 weeks 1
• Organism-specific selection is critical: Terbinafine is more effective for Trichophyton species (T. tonsurans, T. violaceum), while griseofulvin is more effective for Microsporum species (M. canis, M. audouinii) 1, 2
• Treatment should be started immediately when clinical features suggest tinea capitis (scale, lymphadenopathy, alopecia, kerion) even before mycology confirmation 1

Tinea Corporis and Tinea Cruris

• Topical antifungals are first-line for localized disease: Apply for 2-4 weeks, continuing at least one week after clinical clearing 4, 5
• Topical terbinafine 1% applied once or twice daily for 1 week is highly effective due to its fungicidal action 6
• Topical azoles (clotrimazole, miconazole) applied twice daily for 2-4 weeks are effective alternatives 7
• Oral therapy indications: Extensive disease, resistance to topical treatment, immunocompromise, or hair follicle involvement 3, 5, 8
• Oral options when needed: Itraconazole 100 mg daily for 15 days (87% mycological cure rate) or terbinafine 250 mg daily for 1-2 weeks 3

Tinea Pedis

• Topical therapy for 4-8 weeks is standard, with azoles requiring 4 weeks and allylamines requiring only 1-2 weeks 4, 6
• Terbinafine 1% cream applied twice daily for 1 week is significantly superior to clotrimazole 1% cream for 4 weeks 6
• Oral therapy may be needed for extensive or resistant cases 5

Critical Diagnostic Considerations

• Confirm diagnosis before treatment: Obtain KOH preparation, fungal culture, or nail biopsy to identify the causative organism 9, 5
• Clinical diagnosis alone is unreliable as tinea corporis can mimic eczema, and onychomycosis can resemble dystrophic nails from trauma or psoriasis 5
• Specimens should be collected via scalpel scraping, hair pluck, brush, or swab as appropriate 1, 3

Treatment Failure Management

• Initial considerations: Assess compliance, drug absorption, organism sensitivity, and potential reinfection 1
• If clinical improvement occurs but mycology remains positive, continue current therapy for an additional 2-4 weeks 1
• If no clinical improvement, switch to second-line therapy: itraconazole 5 mg/kg/day for 2-4 weeks, or switch between terbinafine and griseofulvin based on organism 1

Important Caveats and Pitfalls

• Avoid combination antifungal-steroid creams as first-line therapy: While they may provide faster clinical improvement, they can cause skin atrophy and other steroid complications, and are not recommended in clinical guidelines 7, 5
• Griseofulvin has important contraindications including lupus erythematosus, porphyria, and severe liver disease 1
• Terbinafine is relatively ineffective against Microsporum species because it cannot be incorporated into hair shafts in prepubertal children and doesn't reach scalp surface arthroconidia 1
• Screen and treat family members for anthropophilic species like T. tonsurans, as over 50% of household contacts may be affected 1, 3
• Clean all fomites (hairbrushes, combs, towels) with disinfectant or 2% sodium hypochlorite solution to prevent reinfection 3

Monitoring and Follow-Up

• Mycological cure, not just clinical response, is the definitive treatment endpoint 2, 3
• Continue follow-up with repeat mycology sampling until clearance is documented 2, 3
• Children receiving appropriate therapy for tinea capitis should be allowed to attend school or nursery 1