Currently, a high increase in the incidence of atopic dermatitis is observed, which, according to various authors, affects up to 5% of the population. Importance of this problem is caused by frequent relapses and the development of severe debilitating forms of the disease that are difficult to treat. In half of cases, the disease can proceed for many years with cycles of intensification and remission and with the typical seasonal dependence. Objective. To study the level of α-defensin (1—3) and endothelin (1—21) in the peripheral blood of patients with atopic dermatitis. Material and methods. The study involved 45 patients (23 adolescents and 22 adults) suffering atopic dermatitis, during exacerbation and remission. The control group included 28 healthy volunteers (10 adolescents and 18 adults) aged 15 to 40 years. The level of endothelin (1—21) and α-defensin (1—3) was determined using test systems from Biomedica Group (Germany) and Hycult Biotech (USA), respectively. Results. The endothelin (1—21) level in adolescents with the common form of atopic dermatitis is 2 times higher than that for the localized form. The same dynamics of endothelin (1—21), but with a less difference, was also observed in adults. Adolescents and adults with localized and common forms of atopic dermatitis during exacerbations were detected with an increased concentration of α-defensin (1—3) compared to that in the control group. Conclusion. In our view, white dermographism in patients with atopic dermatitis is directly related to an increase in the endothelin (1—21) concentration. Increasing the α-defensin (1—3) concentration is probably associated with an inflammatory process in the skin and neutrophil degranulation and/or the presence of a bacterial agent (Staphylococcus aureus).