Background: currently,there is insufficient data on the antifungal activity of activated zinc pyrithione, which is widely used in practice. Taking into account the reports about a significant role ofMalasseziain the pathogenesis of a number of dermatoses, the study of this issue is of scientific, practical interest. Aims:to evaluate the antifungal activity of external forms of activated zinc pyrithione in the treatment of psoriasis, seborrheic dermatitis, pityriasis versicolor. Materials and methods:an open prospective study was conducted between March and July 2022. Patients with psoriasis, seborrheic dermatitis, pityriasis versicolor were treated with external forms of activated zinc pyrithione for 21 days. Skin scales and circular prints from lesion foci, as well as from skin areas without clinical manifestations before and after therapy were studied. A quantitative assessment of skin colonization by micromycetes of Malassezia was performed using microscopic, cultural methods of examination. Clinical efficacy and drug safety of the therapy was assessed using the Dermatological Symptom Scale Index, by recording adverse events at weeks 0, 1, 2, 3. Results:64 patients aged 18 to 65 years with diagnoses of psoriasis, seborrheic dermatitis, and pityriasis versicolor were included. 60 patients completed the study, 4 were excluded due to failure to adhere to the schedule. In patients with seborrheic dermatitis and pityriasis versicolor in the lesion foci after therapy, a significant decrease colonization level according to the results of microscopic, cultural studies was observed. In psoriasis patients, a significant decrease in the colonization level was obtained only based on the results of microscopic examination. In all groups, significant differences in comparison to the initial level were registered already at the 1st week of treatment. No adverse events were registered.

No abstract