Asymptomatic carriage is a condition of positive dermatophyte scalp culture without signs and symptoms of tinea capitis. Carriers are the source of dermatophytes that are able to transfer fungal agents to other people. The aim of this study was evaluating asymptomatic dermatophyte scalp carriage among students of primary schools in Arak city.

Sampling by a sterilized hairbrush from scalp was performed among 3174 students. Hairbrush was inoculated onto Mycosel agar plates. Dermatophyte isolates were identified by PCR-RFLP using MvaI enzyme. In vitro antifungal susceptibility test was done according to the Clinical and Laboratory Standards Institute (CLSI) M38-A2 protocol. The antifungal drugs used included griseofulvin (GRZ), terbinafine (TER), itraconazole (ITC) and fluconazole (FLU).

A total of 3174 schoolchildren were screened, 15 cases (0.48%) had a positive culture for dermatophytes. Asymptomatic carriers including 11 (73.3%) boys and 4 (26.7%) girls and their age range were between 7–12 years. Trichophyton tonsurans (80%), T. interdigitale (13.3%) and T. rubrum (6.7%) were the most common isolated dermatophyte. Based on the obtained antifungal susceptibility results, terbinafine had the lowest and fluconazole had the highest MIC values for all of the tested dermatophyte isolates.

In the study, T. tonsurans was the most common species isolated from asymptomatic carriers and of the four antifungals tested, terbinafine had the most active antifungal in vitro against all isolates. Identifying and treating scalp dermatophyte carriers can prevent the spread of tinea capitis in the community.