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.