Psoriasis is a chronic inflammatory multifactorial disease that can be clinically heterogeneous. In over 80 % of patients, the disease is presented as plaque psoriasis, but it can also be guttate, erythrodermic, pustular and arthropathic. Psoriasis is characterized by extensive inflammation, proliferation and impaired differentiation of the epidermis. Psoriatic plaques are usually found on the scalp, lower trunk, and extensor surfaces of the extremities. They are characterized by well-defined, symmetrical appearance, erythema, infiltration, and scaling. BSA, PASI and DLQI scoring systems are most often used to assess the severity of the disease. The diagnosis is usually established by a detailed history and physical examination, and exceptionally by a biopsy. In patients, it is necessary to determine the presence of comorbidities and, in some cases, to think about the differential diagnosis of psoriasis. Traditionally, the pathogenesis of psoriasis is described through the initiation and maintenance phases of the disease. Already in the 80s and 90s of the last century, psoriasis was already recognized as an immune-mediated disease, which soon led to the development of biological therapy. Biological therapy for psoriasis has brought significant advances in treating moderately severe to severe plaque psoriasis. Today, drugs from the group of TNF-α inhibitors, IL-17 inhibitors, IL-23 inhibitors, IL-12 and -23 inhibitors, and IL-36 inhibitors are used in psoriasis therapy, while new drugs are currently being tested.