Seborrheic dermatitis (SD) is a chronic relapsing multifactorial skin disease characterized by increased secretion of sebum, changes in its qualitative composition and localization in the area of accumulation of sebaceous glands. Modern methods of treating SD do not provide stable long-term remission, which requires the expansion of standard approaches to the treatment of the disease. The etio-logy of the disease is currently an object of study, and any exogenous factor can serve as a trigger - stress, neuroendocrine disorders, improper care, deficiency states. In the literature, relationship between the development of the disease and the activation of yeast-like fungi Malassezia spp., genetic features of sebaceous gland secretion, immunodeficiency states, as well as zinc and nicotinic acid deficiency is the most frequently described. In addition, functional gastrointestinal symptoms are quite common among patients with SD, and their diagnosis and treatment is a complex clinical problem. This article describes a clinical case of successful therapy of a patient with a protracted course of SD using a lactose-free diet.

Keywords: personalized nutrition, seborrheic dermatitis, lactase, lactose, nutrition, diet, inflammation