Comparison of Wood's lamp and dermatophyte test medium for diagnosing Microsporum canis

Abstract

Objective. To compare two methods of diagnosis of Microsporum canis, Wood's lamp (LW) and dermatophyte test metium (DTM). LW is based on the presence of ultraviolet light on dermatophytosis-infected hair in a specific way, it is considered a qualitative test and easy to use, while DTM is an especially useful laboratory test of wide use and more specific, due to the isolation of the genus and species of dermatophyte. Methodology. For the study, two hundred canine patients presenting with generalised dermatological lesions, sampled from skin scrapings, depilation, or brushing, were evaluated. For the identification of the aetiological agent (Microsporum canis), by means of the LW, which is based on emitting yellowish-green fluorescence in the positive case of the presence of M. canis; while the DTM is a culture that allows the growth of the infectious agent which can be seen under the microscope, this is how it is considered a selective and specific microbiological test. Results. They showed that, of the two hundred canine patients analyzed, DTM agar performed 2.26 times better than Wood's lamp in the diagnosis of Microsporum canis, with no significant differences with respect to sex and type of sample taken (hair or scab), with values of 0.069 and 0.145, respectively. Conclusions. We conclude that the most effective method for determining Microsporum canis dermatophytosis is the DTM differential agar.