The paper describes a unique clinical case of severe systemic side effects of topical steroid therapy for psoriasis in a 44-year-old female patient. The long-term irrational use of the highly potent topical corticosteroid clobetasol propionate in large dosages (200 g or more of the ointment base a week) gave rise to psoriatic erythroderma to develop the signs of tachyphylaxis, endogenous Cushing's syndrome, secondary adrenal insufficiency, infectious and other complications. The complex treatment algorithm released jointly by dermatologists, endocrinologists, and internists during long-term follow-up led not only to a considerable improvement of a psoriatic process, but also could normalize the patient's general somatic status.