Psoriasis is a chronic, inflammatory skin disease. Environmental, genetic, autoinflammatory and autoimmune factors play a role in the pathogenesis of disease. It is believed that heat shock protein 90 (HSP90) is an interleukin-17 (IL-17) receptor, which plays an essential role in the psoriasis pathogenesis. To evaluate the expression of the gene encoding HSP90 protein in keratinocytes of patients with psoriasis depending on its duration, recurrences, exacerbating factors, therapy form, and the coexistence of metabolic disorders and cardiovascular diseases. Skin samples from 40 psoriatic patients were investigated in this study. Control skin biopsies were collected from 20 healthy volunteers. HSP90 expression level was measured by qRT-PCR reaction. This study has shown an increased mRNA expression of HSP90 in psoriatic patients as compared to healthy volunteers. A positive correlation of HSP90 expression and the frequency of exacerbations was found. A negative correlation between the HSP90 activity and the age of patients was demonstrated in the coexistence of psoriasis with hyperlipidaemia or diabetes. Among the factors exacerbating psoriasis, acute infections induced HSP90 expression most significantly. HSP90 plays a role in the pathogenesis of psoriasis. The expression of HSP90 increases with the frequency of exacerbations of psoriasis throughout the year. Hyperlipidaemia or diabetes associated with psoriasis in young adults, and acute infections and emotional stress increase the expression of HSP90. The expression of HSP90 in psoriatic patients is not dependent on the type of psoriasis, comorbidity of cardiovascular diseases, smoking and alcohol addiction.