Abstract: Objective To observe the in vitro damage to hairs by Trichophyton mentagrophytes and Microsporum canis using light microscopy and scanning electron microscopy (SEM), and to compare the differences in the duration needed for the two fungi to damage hairs in different age groups. Methods We collected healthy hairs from different age groups, and performed hair perforation test in vitro. The damage to the hairs was observed by SEM and light microscopy. Results Both T. mentagrophytes and M. canis could damage the hairs. The duration needed for T. mentagrophytes to damage the hairs was significantly shorter than that for M. canis in all age groups (P<0.01). In addition, the time needed to damage the hairs increased (P<0.01) with the age for both fungi. Conclusions The damage to hairs by T. mentagrophytes is earlier and more severe than that by M. canis, and the younger the patients, the more easily the hairs are damaged.

Key words: Trichophyton, Microsporum, Hair perforation in vitro, Microscopy, electron, scanning