What is the treatment for ringworm infections?

Treatment of Ringworm (Tinea Corporis)

For localized ringworm infections, topical antifungal therapy with clotrimazole 1% or miconazole 2% cream applied twice daily for 2-4 weeks is the first-line treatment, while oral therapy with terbinafine or itraconazole should be reserved for extensive disease, treatment failures, or when topical application is impractical. 1, 2

First-Line Topical Therapy

For uncomplicated tinea corporis:

• Clotrimazole 1% cream applied twice daily for 2-4 weeks is highly effective and well-supported by evidence 1
• Miconazole 2% cream applied twice daily for 2-4 weeks is an equally effective alternative 1
• Terbinafine cream demonstrates superior efficacy compared to placebo with a number needed to treat (NNT) of 3, meaning only 3 patients need treatment for one additional cure 2
• Naftifine 1% shows strong mycological cure rates (RR 2.38) with similar NNT of 3 2

Treatment duration: Continue for at least one week after clinical clearing to prevent relapse 3

Oral Therapy Indications

Oral antifungal drugs are necessary when:

• Lesions are widespread or cover extensive body surface area 4
• Topical therapy has failed after 2 weeks of appropriate treatment 1
• The infection involves areas difficult to treat topically (near eyes, ears, mouth, or complex skin folds) 4
• Hyperkeratotic lesions are present that don't respond to topical monotherapy 4

Oral Treatment Options

For extensive or resistant cases:

• Terbinafine 250 mg daily for 1-2 weeks is highly effective for tinea corporis 5
• Itraconazole 100 mg daily for 2 weeks OR 200 mg daily for 7 days provides excellent cure rates 5
• Fluconazole 150-200 mg weekly for 2-4 weeks may be considered as an alternative 1, 5
• Griseofulvin 500 mg daily (or 0.5 g daily in divided doses) for 2-4 weeks is FDA-approved for tinea corporis, though generally less favored than newer agents 6

Important caveat: If terbinafine resistance is suspected (particularly with Trichophyton indotineae infections associated with travel to the Indian subcontinent), itraconazole 200 mg/day or higher for a longer duration should be used instead 7

Combination Therapy Considerations

• Topical corticosteroid-antifungal combinations may achieve faster clinical cure (NNT 6) but show no difference in mycological cure rates 2
• These combinations are not recommended in clinical guidelines and should be used with extreme caution due to potential for skin atrophy and steroid-related complications 2, 3
• If inflammation is significant, consider using an antifungal with inherent anti-inflammatory properties rather than adding steroids 3

Critical Pitfalls to Avoid

• Never use topical therapy alone for tinea capitis - oral therapy is mandatory as topical agents cause irritation and enhance inflammation 4
• Griseofulvin is generally ineffective against Trichophyton indotineae and should be avoided for suspected resistant infections 7
• Fluconazole is generally not effective for resistant dermatophyte infections 7
• Do not discontinue treatment when lesions appear clear - continue for at least one additional week to prevent relapse 3
• Confirm diagnosis before treatment with KOH preparation or fungal culture, as ringworm can mimic other conditions 6

Treatment Algorithm

1. Confirm diagnosis with KOH preparation or culture 6
2. Assess extent of disease:
   • Localized, few lesions → Topical therapy (clotrimazole or miconazole) 1
   • Extensive, multiple sites, or difficult-to-reach areas → Oral therapy 4
3. If topical therapy chosen: Apply twice daily for 2-4 weeks, continue 1 week after clearing 1, 3
4. If no improvement after 2 weeks: Switch to oral therapy or different antifungal class 1
5. For oral therapy: Terbinafine 250 mg daily for 1-2 weeks (first choice) OR itraconazole 100-200 mg daily for 1-2 weeks 5
6. If treatment failure occurs: Consider itraconazole at higher doses or longer duration, especially if resistant species suspected 7

Monitoring

• Reassess at 2 weeks - if no improvement with appropriate topical therapy, escalate to oral treatment or switch antifungal class 1
• Address exacerbating factors including skin moisture, hygiene measures, and sources of reinfection 6
• Adverse effects with topical agents are minimal (mainly irritation and burning) and occur infrequently 2