To the Editor We read with great interest the article by Mikailov et al1 on the cost-effectiveness of laboratory testing before treatment of onychomycosis. In this article, the authors did a substantial analysis of the cost and potential harm associated with 3 methods of onychomycosis assessment prior to therapy with oral terbinafine or efinaconazole, 10%. They include the potassium hydroxide and periodic acid–Schiff stainings, which are commonly performed in dermatological practices. Fungal culturing should be included because it is the only test that can prove the viability and identity of the organism. It is particularly important when nondermatophytes or yeast are suspected, which may not respond to terbinafine.
Lipner SR, Scher RK. Confirmatory Testing for Onychomycosis. JAMA Dermatol. 2016;152(7):847. doi:10.1001/jamadermatol.2016.0785