Urticaria induced by preservatives and dye additives in food and drugs.

Abstract

SUMMARY Fifty-two patients with recurrent urticaria or angio-oedema and thirty-three controls have been provoked with five different food dyes and the preservatives sodium benzoate and 4-hydroxy-benzoic acid, as well as aspirin, sulphanilic acid and a placebo. The reaction was judged as positive in thirty-nine patients who developed urticaria within 14 h. Of these, thirty-five reacted to aspirin, twenty-seven to benzoic acid compounds and twenty-seven to azo dyes. The four patients who did not have urticaria after aspirin, reacted with urticaria to benzoic acid compounds, and three of them to azo dyes. No definite pattern for the reaction to the different azo dyes was seen. None had an urticarial reaction from sulphanilic acid, Patent Blue (a non-azo dye) or placebo. The doses of additives used in the provocation tests are easily exceeded in daily life by the consumption of foods and drugs. Recurrences of urticaria could be prevented through the avoidance of food and drugs containing azo dyes and preservatives.