Adverse reactions to tartrazine.

Adverse reactions to tartrazine may cause symptoms involving the skin (urticaria and angioedema, eczema). gastrointestinal tract, respiratory tract and/or central nervous system. Susceptibility appears to be familial, and more widespread than is generally appreciated. There is strong circumstantial evidence that reactions are pharmacological in nature rather than immunological. and specific sensitisation by ingestion is therefore unlikely. Reactions appear to be dose-related. and sensitive patients may exhibit withdrawal reactions and supersensitivity, as well as tachyphylaxis and tolerance after reintroduction. There is extensive cross-reactivity between tartrazine and other dyes we have tested, and also between azo-dyes and other food chemicals. These include not only various preservatives and flavourings. but also natural compounds such as salicylates and amines. Overall, natural salicylates are the single commonest substance to produce reactions when tested by double-blind oral challenge. Most patients are sensitive to multiple substances (between 2 and 10 commonly). and the effects can be additive. it is not known as yet whether there is synergy between specific compounds.