Sensitization to Rice in Allergic Children Pediatric Allergy and Immunology Unit, Children's Hospital, Ain Shams University

Abstract

Background The prevalence of food allergy among Egyptian children is largely unknown, more so for the different food allergens. Although there are several studies reporting on the common food allergens, yet none was done to explore the allergy to rice, a food allergen that is much less recognized both by pediatricians and allergic patients. Objectives To estimate the frequency of sensitization to rice in pediatric allergic patients in Egypt. Patients and Methods This analytical cross-sectional study was carried out in the period from April 2019 to September 2020. The study included 150 physician-diagnosed allergic patients aged 6 months to 18 years, enrolled consecutively from the Pediatric Allergy and Immunology Unit, Children's Hospital, Ain Shams university. They were 90 (60%) males and 60 (40%) females. SPT was done using a commercial rice allergen extract, Prick-to-prick test with cooked rice. Patients with clinical and /or SPT results suggestive of rice allergy were subjected to oral challenge test under medical supervision in hospital. Results None of the screened allergic children (n = 150) gave a self/parentally reported history of allergy to rice, nor after inquiry by the investigator. SPT using commercial rice extract revealed that only 8 reacted positively (>3mm) and were considered sensitized. PPT was done to all patients using a home prepared cooked rice extract and the test was positive in 5 patients; 2 of these were positive also by SPT. A total of 11 patients (7.3%) were considered sensitized and were subjected to OCT and none had a positive test. There was statistically significant difference in age between rice sensitized and non sensitized, being higher in rice-sensitized patients, with p-value = 0.043. Conclusion Our study is a pilot research which draws the attention to the existence of sensitization to rice in allergic children. PPT is a useful test with a reliable specificity which when positive, would aid in diagnosing rice allergy in settings with limited resources and unavailability of rice protein extracts.