Relapse after Oral Terbinafine Therapy in Dermatophytosis: A Clinical and Mycological Study

Background: The incidence of recurrent tinea infections after oral terbinafine therapy is on the rise. Aim: This study aims to identify the appearance of incomplete cure and relapse after 2-week oral terbinafine therapy in tinea corporis and/or tinea cruris. Materials and Methods: A total of 100 consecutive patients clinically and mycologically diagnosed to have tinea corporis and/or tinea cruris were included in the study. The enrolled patients were administered oral terbinafine 250 mg once daily for 2 weeks. All clinically cured patients were then followed up for 12 weeks to look for any relapse/cure. Results: The common dermatophytes grown on culture were Trichophyton rubrum and Trichophyton tonsurans in 55% and 20% patients, respectively. At the end of 2-week oral terbinafine therapy, 30% patients showed a persistent disease on clinical examination while 35% patients showed a persistent positive fungal culture (persisters) at this time. These culture positive patients included all the clinically positive cases. Rest of the patients (65/100) demonstrated both clinical and mycological cure at this time (cured). Over the 12-week follow-up, clinical relapse was seen in 22 more patients (relapse) among those who had shown clinical and mycological cure at the end of terbinafine therapy. Thus, only 43% patients could achieve a long-term clinical and mycological cure after 2 weeks of oral terbinafine treatment. Majority of the relapses (16/22) were seen after 8 weeks of completion of treatment. There was no statistically significant difference in the body surface area involvement or the causative organism involved between the cured, persister, or relapse groups. Conclusions: Incomplete mycological cure as well as relapse is very common after standard (2-week) terbinafine therapy in our patients of tinea cruris/corporis.