Background. One of the current problem of medicine in general and in clinical allergy is becoming urticaria, the incidence of which has been rapidly increasing in recent years. The incidence of urticaria reaches 5% in young children, and 3% in older children. The high frequency of occurrence of urticaria, as well as the variety of causative factors, various pathogenic mechanisms and different peculiarities of therapy make it possible to attribute urticaria to the category of important problems of modern medicine.

Objective. To study of the influence of trigger factors and comorbidities on the clinical course of urticaria in children of different ages.

Patients and Methods. The survey included 215 children with urticaria aged 3 months to 18 years who were hospitalized in the allergy department of the Institute of Maternal and Child Health in the period 2018–2021. To identify comorbid conditions, special questionnaires were filled out, which reflected the results of collecting data on the history of development and allergic history, as well as the results of using a complex of laboratory and instrumental studies. The etiological structure was confirmed using methods for analyzing the results of elimination samples, identifying specific IgE antibodies.

Results. Depending on age, the patients were divided into 4 groups. Group I included 18 children under the age of 1 year; in II — 82 patients aged 1 to 4 years; in III — 94 children aged 5–13 years and group IV included 21 children aged 14 to 18 years. 44% were girls and 56%, respectively, boys. It was found that the occurrence of an acute allergic reaction was associated with food sensitization in 55.5%, with increased sensitization to drugs in 28.5% (antibiotics, antipyretics). Specific IgE antibodies were found more often to citrus fruits, food additives, chocolate, raspberries, strawberries, peaches, honey, watermelon, melon and less often to fish, milk, eggs. In 20% of children, the etiological factor was not identified. Comorbid conditions were detected in 84% of cases, among which pathology of the gastroduodenal system, functional disorders of the hepatobiliary system and pancreas, acute respiratory viral infections, neurological pathology prevailed. Parasitic diseases were found in 33% of patients (intestinal giardiasis in 32 patients, campylobacteriosis in 25, ascariasis in 16, toxocariasis in 9 patients).

Conclusion. The identified features of the etiological structure and comorbid conditions in acute urticaria largely depend on the age of the children. Food sensitization prevails in the group of patients of early age. With age, there is an increase in cases of polyvalent sensitization and comorbid conditions. The most severe course of acute urticaria was noted in the group of patients with clinical manifestations of chronic gastroduodenitis with campylobacteriosis and parasitic diseases. It has been proven that comorbid conditions affect the clinical course and the effectiveness of the treatment of acute urticaria in childhood.