Aim Fish and shrimps are included in «big 8 allergens» and caused severe allergic reactions in children. It is important to consider regional characteristics when determining sensitization profiles. Aim was to determine the prevalence of sensitization to fish and shrimps in children with allergies

Material and Method A cross-sectional study was conducted on 238 children (0 months - 17 years 11 months) with symptoms of allergic rhinitis/atopic eczema/food allergy/asthma, living in the Moscow metropolitan area. Sensitization was detected using ImmunoCAP ISAC (n=143) or ALEX2 (n=95) assay.

Results Sensitization to fish allergens was observed in 14/238 (5%). Most frequently, sensitization to the components of mackerel (Sco s 1) - in 13/95 (12.6%), salmon (Sal s) - in 12/95 cases (11.5%) was observed. 30 (12%) patients reported symptoms when consuming fish, with 10 of them (33%) having sensitization to it. 18 (7%) children had never tried fish. Asymptomatic sensitization to fish was noted in 6/14 (43%) cases. Sensitization to shrimps was observed in 10/238 (4.2%) children, all of them showed sensitization to some house dust mite allergens. Sensitization to northern shrimp (Pan b) was detected in 4/95 (4%), to black tiger shrimp (Pen m 1 and 3) - in 8/238 (3.4%) cases. No sensitization was detected to the common shrimp component Cra c 6. In 7 (3%) patients reported any symptoms when consuming shrimp no sensitization was detected. 57 (24%) patients had never consumed shrimp. Asymptomatic sensitization to shrimp was observed in all patients.

Conclusions Sensitization to fish was more frequent than to shrimp allergens. The prevalence of self-reported allergy to fish was 3 times more common than sensitization, while among those reported any symptoms due to shrimp nobody was sensitized to it. Asymptomatic sensitization to fish was found in almost half of the patients, to shrimps – in all patients.