A Prospective Open-Label Study of the Antifungal Activity of External Forms of Activated Zinc Pyrithione in the Treatment of Malassezia- Associated Skin Diseases

Background: There are insufficient data on the antifungal activity of active zinc pyrithione, which is widely used in practice. Considering the reported role of Malassezia spp. in the pathogenesis of several dermatologic diseases, it is of scientific and practical importance to investigate this issue. Aim: To evaluate the antifungal activity of external forms of activated zinc pyrithione in the treatment of psoriasis, seborrheic dermatitis, and pityriasis versicolor. Method: An open-label prospective study was conducted between March and July 2022. Patients with psoriasis, seborrheic dermatitis, and 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 and 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, and 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 was observed in the colonization level according to the results of microscopic and cultural studies. 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 observed at the 1st week of treatment. There was no adverse events observed. Conclusion: Activated zinc pyrithione in the form of cream and aerosol showed moderate antifungal activity against micromycetes of the genus Malassezia.