Treatment of Ringworm (Dermatophyte Infections)
For tinea corporis and tinea cruris (ringworm of the body and groin), topical antifungal therapy is the first-line treatment, with terbinafine, naftifine, or azoles (such as clotrimazole) applied for 2-4 weeks showing strong efficacy. 1
Topical Therapy for Localized Infections
First-Line Topical Agents
Terbinafine cream is highly effective, achieving clinical cure rates 4.5 times higher than placebo (NNT 3), with treatment duration of 1-2 weeks for most cases 1
Naftifine 1% demonstrates strong mycological cure rates (RR 2.38 compared to placebo, NNT 3) and clinical cure rates (RR 2.42, NNT 3) 1
Azole antifungals (clotrimazole, miconazole, ketoconazole) show mycological cure rates nearly 3 times higher than placebo (RR 2.87, NNT 2) when applied twice daily for 2-4 weeks 1
Practical Application Strategy
Apply topical antifungals once or twice daily (depending on the specific agent) for 2-4 weeks, extending 1-2 weeks beyond clinical resolution to prevent relapse 1
Terbinafine and naftifine (allylamines) offer the advantage of shorter treatment duration (1-2 weeks) compared to azoles (2-4 weeks) 1
There is no significant difference in mycological cure rates between azoles and benzylamines (RR 1.01), so choice can be based on cost, availability, and application frequency 1
Systemic Therapy Indications
When Oral Treatment is Required
Tinea capitis (scalp ringworm) always requires systemic therapy because topical agents cannot adequately penetrate hair shafts 2
Extensive or severe infections in immunocompromised patients warrant oral antifungal therapy due to more widespread and difficult-to-treat disease 3
Tinea unguium (onychomycosis) requires oral therapy, as topical treatment (except ciclopirox) is not indicated for nail infections 3
Oral Antifungal Options
Griseofulvin is FDA-approved for tinea capitis, requiring 6-8 weeks of treatment 2
Terbinafine (Lamisil) is FDA-approved for tinea capitis with a shorter 6-week treatment course 2
Itraconazole is effective for various superficial and invasive fungal infections, though it has significant CYP3A4 inhibition and drug interaction potential 4, 3
For immunocompromised patients requiring oral therapy, terbinafine has a lower drug-drug interaction potential compared to itraconazole, making it preferable in patients on multiple medications 3
Critical Pitfalls to Avoid
Do not use topical corticosteroid-antifungal combinations for more than 2 weeks for tinea cruris or 4 weeks for tinea pedis/corporis, as prolonged use can suppress local immunity and allow deeper fungal invasion 5
Avoid corticosteroid combinations entirely in children under 12 years, on facial lesions, in diaper areas, or in immunosuppressed patients 5
Never use topical therapy alone for tinea capitis or onychomycosis, as it will fail to achieve cure 2, 3
Ketoconazole should be avoided for systemic use due to significant hepatotoxicity and drug interactions 6
Special Considerations
Adverse effects from topical antifungals are minimal, typically limited to mild irritation and burning, with no significant difference between active treatments and placebo 1
For inflamed lesions in otherwise healthy adults, a low-potency nonfluorinated corticosteroid combination may be used initially for symptom relief, but must be switched to pure antifungal once symptoms improve 5
Treatment should extend beyond visible clinical resolution to ensure complete mycological cure and prevent relapse 1