Background: The European Parliament and the Council of the European Union have issued a new directive on information on the label about the ingredients present in foodstuffs. Twelve foods causing hypersensitivity are now subject to particularly strict labelling rules. Among these foods is mustard, which until now has been little recognised as a food allergen in Norway.
Materials and methods: Literature searches in Medline were performed and supplemented by manual searches of reference lists.
Results: Since the first published case of mustard allergy in 1980, a number of case reports and patient series have been published. Most reports come from certain regions of France, and a majority of the studies have been performed by a limited number of investigators. Symptoms triggered by mustard cover the whole range from full-blown systemic anaphylactic reactions to pollen-food allergy syndrome-like local reactions. Frequently, reactions appear to be serious. Mustard allergy has on many instances been found in small children. Cross-reactivity apart from that among different types of mustard does not appear to be a clinical problem. Mustard allergens are resistant to heat and food processing.
Interpretation: With more attention being given to mustard as a food allergen because of the new labelling rules, it will most likely soon become apparent whether mustard is a food allergen of importance in Norway. The Norwegian national reporting system and register of severe allergic reactions to food will be an important tool in this context.