Resistant dermatophytes ‘are coming’
Halting treatment with an oral drug at a particular time point instead of when the nail is fungal-free likely contributes to resistant strains, she added, noting that she has at least two dozen patients in her practice with dermatophyte resistance documented in labs. “We need to be antifungal stewards, because resistant dermatophytes are coming to us,” she said. “They’re here already, and we don’t want it to be endemic in the U.S.”
In a published study from 2020, researchers from India enrolled 200 patients with relapsing tinea corporis, tinea cruris, and tinea faciei and allocated 50 each to treatment with either fluconazole, griseofulvin, itraconazole, or terbinafine. At week 4, all treatment arms had cure rates of less than 8%. At week 8, the cure rates were 42% for fluconazole, 16% for griseofulvin, 28% for terbinafine, and 66% for itraconazole.
Based in part on these study findings, Dr. Elewski said that she has become more aggressive in her therapeutic approach, including treating some of her patients on terbinafine for a minimum of 6 months. “If that’s not enough, I keep treating,” she said. “But, patients may not respond to terbinafine; we see resistance. So, itraconazole may be our best drug going forward for treating onychomycosis. You just have to watch out for side effects of itraconazole, mainly drug-drug interactions.”
Dr. Elewski reported having no relevant financial disclosures related to her presentation.