Rice allergy J13.1; T78.1

Rice is one of the most important crops on earth: it is the staple food for more than half of the world's population. The rice plant belongs to the grass family. Its origins probably lie in the deltas of the Ganges, Yangtze, Euphrates and Tigris rivers. However, the actual wild form of this useful plant has been lost.

About 8000 rice varieties exist today and have been adapted by breeding to a wide range of climates and conditions. Rice plants mostly need the warmth and humidity of the subtropical climate to thrive. Most varieties grow in swampy soil. However, there are also rice varieties that manage with relatively small amounts of water (so-called dry rice). From Africa comes Oryza glaberrima, also known as African rice. The so-called "wild rice" is also popular as a foodstuff, but it does not belong to the well-known Oryza varieties, but to the group of sweet grasses.

Sensitizations against rice seem to be very rare. However, they can lead to threatening circulatory reactions. Gastrointestinal complaints are usually in the foreground (Jäger L et al. 2001). Nowak-Węgrzyn A et al. described a "Non-IgE-mediated gastrointestinal food allergy" in infants caused by rice products.

IgE antibodies are directed against glutelins and globulins. However, these allergens lose 40-70% of their allergen activities when heated (Jäger L et al. 2001). Ory s 1 (beta-expansin) and Ory s 12 (profilin A) are identified as allergens. Cross-reactions exist to wheat, corn and millet (Yamada K et al. 1993). Further different Cross reactions exist to grass pollen, whereby mainly sensitisation to beta-expansin (EXP) and extensin (EXT) can be detected (Hirano K et al.2013).

Rice is also used in cosmetics. In the INCI nomenclature it is labelled with "Oryza" or "Rice".

1. Gu D et al (2017) Quantitative Classification of Rice (Oryza sativa L.) Root Length and Diameter Using Image Analysis.PLoS One 12:e0169968.
2. Hirano K et al (2013) Allergenic potential of rice-pollen proteins: expression, immuno-cross reactivity and IgE-binding. J Biochem 154:195-205.
3. Jäger L et al (2001) Food allergies and intolerances. Urban & Fischer Publishing House Munich, Jena S 120-121
4. Nowak-Węgrzyn A et al. (2015) Non-IgE-mediated gastrointestinal food allergy. J Allergy Clin Immunol 135:1114-1124.
5. Yamada K et al (1993) Cross-allergenicity between rice and buckwheat antigens and immediate hypersensitive reactions induced by buckwheat ingestion. Aerugi 42: 1600-1609