A pediatric case of food-dependent exercise-induced anaphylaxis due to rice bran.

Food-dependent exercise-induced anaphylaxis (FDEIA) caused by fruits and vegetables is increasing in recent years, but rice-induced FDEIA is rarely reported. The mechanism of FDEIA is unclear, although percutaneous sensitization occurs in some cases. A 14-year-old adolescent came our hospital who had 6 episodes of unknown FDEIA occurring from age 13. He affected atopic dermatitis in infancy, and he had been polishing rice daily to help with housework, and also had occasionally begun to observe urticaria while bathing after eating rice from 5 years old. Antigen-specific immunoglobulin E antibody titers (ImmunoCAP) were 1.35 UAmL for rice, 23.6 UAmL for orchard grass. Oral food challenge and exercise provocation test with polished rice were negative. An oral food challenge with rice bran was also negative, but exercise provocation test induced severe anaphylaxis. IgE immunoblotting with rice bran detected patient-specific bands, as 25-, 35-, 50-, and 60 kDa, and the 25- and 60-kDa bands were heat-resistant. In a suppression test using rice bran, these bands disappeared or diminished. In an inhibition test against orchard grass pollen with rice bran, inhibition was not observed. Conversely, an inhibition test against rice bran with orchard grass pollen, inhibition was observed in a concentration-dependent manner. This is extremely rare case of FDEIA in children, caused by rice bran. Furthermore, it might be induced by percutaneous sensitization. In FDEIA, it is necessary to scrutinize the possibility that rice bran may be the cause even in children.