Fungal infections in cats and dogs

Fungal infections are an important cause of dermatoses in cats and dogs that can be investigated by veterinary nurses in general practice and treated under veterinary direction. When working up a skin case at first presentation, mycoses (conditions caused by fungi) should be on the differential list, however some mycoses are more common than others. This article aims to provide a brief overview of the presentation, aetiology, diagnosis, and treatment of various dermatomycoses.

Malassezia is a genus of lipid-dependent yeasts that can be found as part of the normal flora on the skin of many animals. The most common species in dogs and cats is Malassezia pachydermatis, (Guillot and Bond, 2020) although there are several others, including Malassezia furfur and Malasse-zia sympodialis that can be seen in other animals as well as cats. Malassezia spp. dermatitis or otitis are the most common fungal skin infections seen in dogs (Bond et al, 2020); and studies have indicated that the peri-oral region and interdigital skin is frequently colonised (up to 80%) by M. pachydermatis in healthy dogs of various breeds (Guillot and Bond, 2020). Malassezia organisms were also found on cytology from the ears of over a third of cats in one study, and are known to be part of the normal ear flora (Tyler et al, 2019), although the prevalence of Malassezia spp. causing disease has not been fully investigated.