Pathogenesis, diagnosis and pharmacotherapy of dermatophytosis in cats

This review article describes the diagnosis and pharmacotherapy of dermatophytosis in cats. Dermatophytosis is a common contagious infectious disease of companion animals caused by keratinophilic filamentous fungi belonging to the phylum Ascomycota. Fungal skin infections in animals, particularly in cats, occur in various breeds and age groups. Persian cats are more susceptible to the disease, and young animals are more commonly affected. The severity of dermatophytosis in these animals is influenced by primary immunodeficiency, inadequate husbandry, and coat characteristics. Adult cats are typically asymptomatic carriers of this cutaneous pathology. Subclinical infections are common in cats, especially in long-haired animals. Factors contributing to the development of dermatological pathology include immunosuppression, dietary protein and vitamin A deficiency, and high environmental temperature and humidity. Diagnosis of dermatophyte infection in cats is comprehensive and includes history taking, evaluation of clinical findings, and mandatory laboratory confirmation. The clinical course of dermatophytosis is variable and depends on multiple factors (location of lesions, sex, age, the animal's immune status, and the causative agent species). The most consistent clinical sign is single or multiple circular areas of alopecia of varying size. In some animals, ring-shaped lesions with central healing and small follicular papules and crusts at the periphery are characteristic. Skin lesions in feline dermatophytosis are typically asymmetric. Pruritus is usually mild or absent. Lesions initially appear on the muzzle and ears; subsequently, the disease progresses with hair loss, papules, scales, erythema, follicular plugging, and hyperpigmentation of the limbs. Laboratory diagnosis of dermatophytosis is complex. Screening for Microsporum canis infection is performed using Wood’s lamp examination. The most sensitive method for identifying fungal species is culturing biological material on Sabouraud dextrose agar. Modern diagnostic methods for dermatophytosis in animals include microscopic examination of biological samples and histological, histopathological, and immunohistochemical analyses. In certain cases, polymerase chain reaction (PCR) is used for diagnostic purposes. Therapy of dermatophytosis in cats involves a combination of topical antifungal agents (enilconazole, miconazole, climbazole, chlorhexidine) and systemic antifungal drugs (terbinafine, itraconazole, fluconazole, ketoconazole, lufenuron). A novel approach to treating dermatophytosis is the use of the mycoparasitic fungus Pythium oligandrum.