This paper highlights the urgency of fungal disease problem among dermatological patients. The etiology, pathogenesis and topical treatment of dermatomycoses are thoroughly examined. The impact of skin pathogenic microorganisms on the pathological process is discussed as well as their mutual influence on each other. The role of local factors in maintaining the skin’s barrier function was studied in detail. Comparative efficacy assessment of two topical medications in the form of gel: terbinafine and combined interferon-based medication (terbinafine + metronidazole + interferon alpha-2b) was conducted at the Moscow Scientific and Practical Center of Dermatovenerology and Cosmetology. Clinical examples of topical mycosis treatment efficacy with monotherapy (terbinafine) and in complex therapy with the examined combined medication (terbinafine + metronidazole + interferon alpha-2b) are presented. Our study included 80 patients: 40 with foot mycoses and 40 with skin mycoses. All patients were divided into four equal groups. The results obtained allow us to recommend combined medication (terbinafine + metronidazole + interferon alpha-2b) as an effective agent for topical treatment of skin mycosis.