Eryth rosin

Urticaria due to intake of tartrazine is more widely accepted as an adverse effect and has been demonstrated in a number of studies. During this reaction substances such as histamine are released into the blood which cause the symptoms of red weals on the skin and itching. A number of other food colours and other types of food additives can also cause urticaria and there may be cross-reactivity between colours such as eryth-rosine and sunset yellow. A challenge of patients whose urticaria had improved on a colour-free diet with 0.15 mg of tartrazine, resulted in three out of thirteen developing urticaria within three hours of exposure."... 

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