What is the recommended treatment protocol for dermatophytosis in dogs and cats?

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Successful treatment of dermatophytosis in cats and dogs requires concurrent systemic antifungal therapy and topical whole-coat disinfection — neither alone is sufficient. 16 Itraconazole is the systemic drug of choice for cats, with terbinafine as the established alternative. 6 Itraconazole is the only FDA-approved oral treatment for cats with Microsporum canis. 4 Griseofulvin is not recommended due to adverse event risk, and ketoconazole and fluconazole are less effective options. 8 For topical therapy, twice-weekly whole-body drenches are the standard approach. Lime sulfur (LS) and enilconazole have been the recommended topical drenches for shelter cats, both providing residual antimicrobial activity on the haircoat after application. 4 Enilconazole body rinse or miconazole with or without chlorhexidine are the topical treatments recommended by the ABCD guidelines. 6 Veterinary LS is no longer available in Canada except in compounded form, and enilconazole is no longer available in North America. 4 A 2% miconazole / 4% chlorhexidine shampoo is an established topical alternative. 13 Topical terbinafine 1% cream applied twice daily achieved mycological cure in cats within 20.3 ± 0.88 days, compared to 28.4 ± 1.14 days with econazole nitrate 1% cream; econazole was also associated with skin redness and irritation at the application site. 9 Mycological cure is defined as two consecutive negative fungal cultures, consistent with the standard endpoint used in clinical trials. 4 Treatment must be continued until this endpoint is reached, not merely until clinical lesions resolve. In shelter and cattery settings, systemic and topical treatment must be accompanied by intensive environmental decontamination. 6 Arthrospores can survive in the environment for approximately one year and are transmitted via direct contact, fomites, brushes, clothing, and dust particles. 6 Prognosis is generally good, particularly in young animals. Dermatophytosis is self-limiting and will reso