Treatment of Ringworm (Tinea Corporis/Cruris/Pedis)
For typical ringworm infections, topical terbinafine applied twice daily for 1-2 weeks is the recommended first-line treatment, with oral terbinafine 250 mg daily for 2-4 weeks reserved for extensive disease, treatment failure, or immunocompromised patients. 1, 2
Topical Therapy (First-Line for Localized Disease)
Preferred Topical Agent
- Terbinafine 1% cream is the most effective topical option 1, 2, 3
- Apply twice daily (morning and night) for 1 week for tinea corporis and tinea cruris 1
- Apply twice daily for 2 weeks for tinea pedis on bottom or sides of foot 1
- Between toes: apply twice daily for 1 week 1
- Wash affected skin with soap and water and dry completely before applying 1
- Continue treatment for at least one week after clinical clearing 4
Alternative Topical Agents
- Naftifine 1% demonstrates superior efficacy compared to placebo (NNT 3) and requires fewer applications than older agents 3
- Clotrimazole 1% is effective (NNT 2 for mycological cure) but requires more frequent application 3
- Other azoles (miconazole, ketoconazole) are reasonable alternatives with similar efficacy 3, 4
Critical Topical Therapy Considerations
- Avoid combination antifungal-corticosteroid products as routine first-line therapy - while they may provide faster symptom relief, they risk promoting resistance and should be reserved for highly inflammatory cases 2, 3
- Topical therapy duration: 2 weeks for tinea corporis/cruris, 4 weeks for tinea pedis 4
- Address moisture control and hygiene measures concurrently 5, 1
Oral Therapy (For Extensive or Refractory Disease)
When to Use Oral Antifungals
- Extensive body surface area involvement 2
- Lack of response to topical treatment 2
- Immunocompromised patients 2
- Hair follicle involvement 2
Preferred Oral Agent
Alternative Oral Agents
- Itraconazole 200 mg daily for longer duration or higher doses may be needed 2, 7
- Fluconazole is less effective against dermatophytes than terbinafine but can be used 8, 2
- Griseofulvin is now primarily reserved for tinea capitis; dosing is 500 mg daily for adults, with treatment for 2-4 weeks for tinea corporis 5
Emerging Resistant Infections (Trichophyton indotineae)
Recognition and Management
- Suspect resistant dermatophyte infection if no improvement with standard terbinafine therapy 7
- Associated with travel to Indian subcontinent or contact with travelers 7
- Terbinafine is ineffective due to squalene epoxidase gene mutations 7
Treatment for Resistant Cases
- Itraconazole 200 mg/day or higher for prolonged duration is the primary alternative 7
- Fluconazole and griseofulvin are generally not effective 7
- For refractory cases: consider off-label voriconazole or posaconazole 7
- Topical non-allylamine antifungals may be used as adjunct therapy 7
Essential Hygiene and Adjunctive Measures
- Concomitant hygiene measures are mandatory to prevent reinfection 5
- For tinea pedis: wear well-fitting, ventilated shoes and change shoes/socks at least once daily 1
- Topical agents are usually required as adjuncts even with oral therapy, particularly for tinea pedis 5
- Yeasts and bacteria may coexist with dermatophytes in tinea pedis - antifungal therapy alone will not eradicate these 5
Diagnostic Confirmation
- Accurate diagnosis with potassium hydroxide preparation or culture is essential before treatment 5, 2
- Clinical diagnosis alone is unreliable - tinea corporis mimics eczema, and onychomycosis mimics trauma or psoriasis 2
- Consider specialized testing if suspected resistant infection 2, 7
Common Pitfalls to Avoid
- Do not discontinue medication prematurely - continue until organism is completely eradicated to prevent relapse 5
- Avoid routine use of antifungal-steroid combinations to prevent resistance development 2
- Recognize that treatment failure may indicate resistant species requiring alternative therapy 7
- Wash hands after each topical application to prevent spread 1