D1.68 - Rice allergy: a case report

Background

Rice (Oryza sativa) serves as a staple food for over half of the global population. Despite its widespread consumption, the prevalence of IgE-mediated rice allergy is considered low, particularly in the UK and Europe. Reports of immediate hypersensitivity reactions following rice ingestion remain rare.

Case presentation

We report a case of a 20-year-old female who developed cutaneous symptoms immediately after eating prawns with rice; the symptoms responded to antihistamines. She subsequently experienced episodes of anaphylaxis after consuming rice in different dishes, including rice with chicken, Chinese meals, and sushi, which required treatment with adrenaline and hospitalization. Apart from rice and shellfish, she has reintroduced all the other implicated foods with no reproduction of her symptoms. Her past medical history included childhood asthma and eczema. She had a positive skin prick test to grass pollen, and negative results to other inhalant allergens and shellfish. Multiplex specific IgE testing with allergen components showed sensitisation to Timothy grass (Phl p 1) and cat (Fel d 4). The specific IgE to rice was positive (19.70 kUA/L, reference range < 0.35 kUA/L). Her total IgE and baseline mast cell tryptase were unremarkable.

Discussion

Rice-induced anaphylaxis has been linked to lipid transfer proteins (LTP) in rice seeds, yet there is no evidence of in vitro sensitization to LTP in this case. Additionally, rice belongs to the grass family and is known to cross-react with rye and Bermuda grass pollens, as well as with other cereal grains in the Poaceae family. However, our patient neither experienced symptoms when consuming other cereals nor reported allergic rhinitis related to grass pollen. This suggests that the rice allergy is isolated, unrelated to LTP syndrome, and not caused by cross-reactivity with grass pollens or other cereals.

Conclusion

To the best of our knowledge, this is the first reported case of an IgE-mediated allergy induced by rice ingestion in the United Kingdom. Given that rice is among the most widely produced and consumed cereals worldwide, it should be considered a potential cause of food allergy, particularly in atypical or unclear presentations.