What is the treatment for ringworm infections?

Treatment of Ringworm Infections

For ringworm (tinea corporis and tinea cruris), topical antifungal therapy with terbinafine 1% cream applied once or twice daily for 1-2 weeks or topical azoles (clotrimazole 1% or miconazole 2%) applied twice daily for 2-4 weeks are the first-line treatments, with terbinafine offering superior efficacy and shorter treatment duration. 1, 2, 3

First-Line Topical Therapy

Allylamine Agents (Preferred for Efficacy and Duration)

• Terbinafine 1% cream applied twice daily for 1 week is highly effective, achieving mycological cure rates of 93.5% compared to 73.1% for clotrimazole at 4 weeks 3
• Terbinafine is fungicidal (kills fungi) rather than fungistatic (inhibits growth), allowing for shorter treatment courses and lower recurrence rates 4
• Naftifine 1% cream is another effective allylamine option, demonstrating significantly higher mycological cure rates compared to placebo (RR 2.38, NNT 3) 2

Azole Agents (Effective Alternative)

• Clotrimazole 1% cream applied twice daily for 2-4 weeks is an effective alternative, particularly for intertriginous areas like the axilla 1, 2
• Miconazole 2% cream applied twice daily for 2-4 weeks provides similar efficacy to clotrimazole 1, 5
• Azoles are fungistatic and require longer treatment duration (typically 2-4 weeks) compared to allylamines 4, 6
• Clotrimazole demonstrates mycological cure rates significantly better than placebo (RR 2.87, NNT 2) 2

Treatment Duration by Site

• Tinea corporis (body): 2-4 weeks for azoles, 1-2 weeks for allylamines 7, 6
• Tinea cruris (groin): 2-4 weeks for azoles, 1-2 weeks for allylamines 7, 6
• Tinea pedis (feet): 4-6 weeks for azoles, 1-2 weeks for allylamines 7, 6
• Treatment should continue for at least one week after clinical clearing to prevent recurrence 6

Systemic Therapy Indications

Oral antifungal therapy is indicated when:

• The infection covers an extensive body surface area 6
• Topical therapy has failed after appropriate duration 1
• The patient is immunocompromised 7
• Infection involves the scalp (tinea capitis) or nails (tinea unguium) 8, 7

Oral Treatment Options

• Griseofulvin 500 mg daily (or 10 mg/kg/day in children over 2 years) for 2-4 weeks for tinea corporis 8
• Oral fluconazole 150-200 mg weekly for 2-4 weeks may be considered for extensive or resistant cases 1

Critical Adjunctive Measures

• Keep affected areas dry, especially in intertriginous locations (groin, axilla, under breast) where moisture accumulates 9
• Address predisposing factors including diabetes, obesity, excessive moisture, and sources of reinfection 9, 8
• Concomitant topical therapy is usually required for tinea pedis, as yeasts and bacteria may be involved alongside dermatophytes 8

Common Pitfalls to Avoid

• Do not stop treatment when skin appears healed (usually after 1 week) if using fungistatic agents, as fungi will recur more frequently 4
• Confirm diagnosis mycologically before treatment with potassium hydroxide preparation or culture, as clinical appearance alone can be misleading 8, 6
• If no improvement after 2 weeks of appropriate therapy, switch to a different class of antifungal agent 1
• Avoid ketoconazole due to significant hepatotoxicity and drug interactions 10

Adverse Effects

• Adverse effects are generally minimal with topical antifungals, consisting mainly of local irritation and burning 2
• No significant difference in adverse effects between active interventions and placebo in most studies 2

Special Considerations for Specific Locations

Axillary Ringworm

• Clotrimazole 1% or miconazole 2% cream applied twice daily for 2-4 weeks 1
• Maintain dryness with absorbent powder after antifungal application 9

Inframammary (Under Breast) Fungal Infections

• Topical azoles (clotrimazole or miconazole) applied twice daily for 2-4 weeks with emphasis on keeping area dry 9
• For moderate to severe cases, oral fluconazole 100-200 mg daily for 7-14 days 9