Objective. Determination of the role of neuropeptides and p-endorphin in developmental mechanisms of atopic dermatitis, and assessment of the effectiveness of levocetirizine, a modern Hl-antihistamine, on atopic dermatitis symptoms and its influence on the SCORAD index in children with atopic dermatitis. Materials and methods. 84 children with atopic dermatitis of moderate-to-severe or severe clinical nature, aged 1 to 17 years, were enrolled in this (double-blind or open, randomised, etc.) study. Patients were treated with levocetirizine 5 mg once daily during 14 days. The levels of P substance, neurokinin A, neurokinin B, and p-endorphin in blood serum, as well as levocetirizine effectiveness on disease symptoms and the SCORAD index were evaluated. Results. Lower neuropeptide levels were associated with disease severity; children with severe atopic dermatitis had lower neuropeptide values. Before treatment, SCORAD index in children with severe atopic dermatitis was 76,5±11,3, and after 7 days of therapy SCORAD index was 14±6,2 points (p< 0,01). By the 7th day after treatment initiation, the acute atopic dermatitis became of subacute nature and was accompanied by a regression of the cutaneous eruption in the form of significant decreasing of skin manifestations and pruritus, absence of new eruption and normalized sleep. In children with moderate-to-severe atopic dermatitis the SCORAD index before levocetirizine treatment was 44,2±3,4 points; on the 3rd day, this index was 20,4±2,6 points; and on the 7th day there was a complete absence of clinical symptoms of the main disease. Levocetirizine administration led to the disappearance of the disease clinical symptoms and pruritus in children with moderate-to-severe atopic dermatitis. Conclusion. This trial demonstrated that neuropeptides are involved in the developmental mechanisms of atopic dermatitis and that levocetirizine can significantly improve the signs and symptoms of children with moderate-to-severe or severe atopic dermatitis.