Rising Antifungal Resistance Poses a Threat to Onychomycosis Treatment

Rising and spreading antifungal resistance poses a threat to treatment of onychomycosis, a common infection of the nail, according to a poster¹ presented at the 2023 Society of Dermatology Physician Assistants (SDPA) Annual Summer Dermatology Conference in Boston, Massachusetts.

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In the study review, researchers Elewski et al sought to review published data related to Trichophyton antifungal resistance, or fungus responsible for most causes of toenail onychomycosis in both the United States and Europe. Additionally, they investigated methods of counteraction against antifungal resistance and the role of topical antifungals in combatting resistance. They cited expanding literature discussing the emerging threat of antifungal resistance, particularly within species of Trichophyton.

Researchers also noted that “antifungal stewardship programs and topical antifungal agents can be used to counteract the spread of antifungal resistance and improve outcomes in the treatment of onychomycosis.”

As a result, researchers found that resistance among Trichophyton species against 2 of the most common oral antifungal treatments for onychomycosis, itraconazole and terbinafine, has not only been detected globally but is rising worldwide. In addition to the rising issue of antifungal resistance, reduced antifungal efficacy is also a growing problem, according to researchers.

Several factors may contribute to both reduced antifungal efficacy and antifungal resistance itself, including:

• Empirical diagnostic and treatment patterns
• Fungal adaptations
• Patient characteristics, such as drug interactions or immunocompromised status

However, promising in vitro research has shown that topical antifungal treatments such as ciclopirox, efinaconazole, and tavaborole, possessed low potential for antifungal resistance development. Furthermore, these treatments, both alone and when combined with oral antifungal treatments, were efficacious within species of Trichophyton.

“The rise and spread of antifungal resistance presents a growing threat to the management of onychomycosis and other superficial fungal infections,” Elewski et al wrote. “Real-world long-term data are needed to monitor global rates of antifungal resistance and the efficacy of oral and topical antifungals, alone or in combination, in counteracting antifungal resistance in the treatment of onychomycosis.”

Reference

1. Elewski B, Gupta A, Joseph W, Lipner S, et al. Treatment of onychomycosis in an era of antifungal resistance: role for antifungal stewardship and topical antifungal agents. Poster presented at the 2023 Society of Dermatology Physician Assistants (SPDA) Annual Summer Dermatology Conference; June 22-25, 2023; Boston, MA.