Modern pathogenetic therapy of psoriasis is the use of suppressive methods aimed to suppress immune reactions in the dermis, synovia, enthesis and eliminate the imbalance between anti-inflammatory and pro-inflammatory cytokines, chemokines. Today, genetically engineered biological drugs are one of the most promising pharmacotherapy achievements for the management of psoriasis, psoriatic arthritis in the group of immunosuppressive agents. Knowing the pathogenetic mechanisms that underlie the development of these diseases allows us today to highly selectively target the top key links of the immunopathogenetic cascade using genetically engineered biologicals, while barely affecting the protective factors of the patient’s immune system unlike the standard backbone (what is referred to as traditional) anti-inflammatory therapy. The treatment of psoriasis in children and adolescents practically involves the same drugs and methods as in adults. However, most of them are used in paediatric practice for conditions for which they are not clearly indicated, and studies on their efficacy and safety are still missing. Currently, it is possible to treat children and adolescents with genetically engineered biological drugs. Ustekinumab, etanercept, adalimumab, secukinumab, and ixekizumab are approved for use in moderate to severe psoriasis in the Russian Federation. In paediatric practice, the genetically engineered biological drug ustekinumab is one of the most effective, safe and convenient for the delivery of therapy (short induction cycle, rare infusions of the drug during maintenance therapy). The article describes the case study of the effective treatment of a 17-year-old patient with severe, continuously recurrent psoriasis. The targeted therapy, including the use of genetically engineered biological drugs, is increasingly being used to treat childhood psoriasis. Moreover, there are now more and more supporters among dermatologists who believe that genetically engineered biological drugs can be prescribed as the first-line drugs for the treatment of moderate to severe psoriasis in children and adolescents.