Summary
Background. To discuss the clinical features and differences between psoriasis, melanoma, squamous cell carcinoma, and basal cell carcinoma. To evaluate whether psoralen plus ultraviolet A therapy, used in the treatment of severe psoriasis, increases the risk of developing skin cancer.
Background. The aim of the study is to investigate psoriasis patients’ knowledge about the treatment of their disease.
Material and methods. In 2016 at the Vilnius University Hospital Centre of Dermatovenereology was conducted a survey which involved 121 patients. The original anonymous questionnaire consisted of 32 questions. The data were processed usjng SPSS 24.0 software. Results considered reliable at p<0.05.

