In a patient with uncomplicated tinea corporis, cruris, or faciei who has not responded to a 2–4‑week course of topical clotrimazole 1 % cream, is it appropriate to switch to terbinafine, and what topical or oral regimen should be used?

Switching to Terbinafine After Clotrimazole Failure

Yes, switching to terbinafine after clotrimazole failure is appropriate and evidence-based for tinea corporis, cruris, or faciei, with terbinafine demonstrating superior efficacy to clotrimazole in multiple clinical trials. 1

Topical Terbinafine Regimen (First Choice)

Apply terbinafine 1% cream once daily for 1-2 weeks. 1, 2

• Topical terbinafine 1% achieves mycological cure in >80% of patients with tinea corporis/cruris 3
• A 7-day once-daily course achieves 84.2% mycological cure versus 23.3% with placebo 2
• Terbinafine 1% emulsion-gel applied once daily for 1 week is significantly more effective than ketoconazole 2% cream, achieving 94% mycological cure versus 69% 4
• Topical terbinafine is more effective than clotrimazole 1% cream in head-to-head comparisons 3

Alternative: Ciclopirox Olamine

If terbinafine is unavailable or not tolerated, use ciclopirox olamine 0.77% cream/gel applied twice daily for 4 weeks. 1

• Ciclopirox provides a different mechanism of action and achieves approximately 60% cure at end of treatment and 85% cure two weeks after completion 1
• This agent shows superior efficacy to clotrimazole 1

Oral Terbinafine for Extensive Disease

For extensive tinea corporis/cruris or cases resistant to topical therapy, use oral terbinafine 250 mg once daily for 2-4 weeks (for patients >40 kg). 1, 5

• Oral terbinafine achieves mycological cure in >80% of patients with tinea corporis/cruris 3
• Even 1-week oral therapy (250 mg daily) is highly effective, with all patients achieving negative mycology at 6-week follow-up 5
• Oral terbinafine is more effective than ketoconazole 200 mg/day in tinea corporis/cruris 3

Critical Treatment Endpoint

The endpoint of treatment must be mycological cure (negative microscopy and culture), not just clinical improvement. 1

• Clinical appearance may improve while infection persists 1
• If clinical improvement occurs but mycology remains positive, continue therapy for an additional 2-4 weeks 1
• Treatment should continue for at least one week after clinical clearing 6

Contraindications to Oral Terbinafine

Oral terbinafine is contraindicated in: 1

• Active or chronic liver disease
• Lupus erythematosus
• Porphyria
• Known hypersensitivity to terbinafine

Common Pitfalls

• Do not stop treatment based solely on clinical appearance – always confirm mycological clearance 1
• Consider underlying risk factors such as obesity and diabetes, which may affect treatment response 7
• Be aware of drug interactions – terbinafine interacts with cyclosporine, fluconazole, and caffeine 1
• Warn patients about rare but permanent taste disturbance with oral terbinafine 8

Prevention of Recurrence

• Avoid skin-to-skin contact with infected individuals 1
• Do not share towels or personal items 1
• Keep affected areas dry 6