David J. Amrol, MD

Almost never — and testing for additives is rarely indicated.

Chronic idiopathic urticaria affects 1% of the population and is defined as hives with no discernable cause that persist for 6 weeks or longer. Many patients worry that foods or occult food additives cause their hives, but little evidence supports this association.

One hundred adolescent and adult patients with chronic idiopathic urticaria were evaluated at a single allergy clinic; 43 reported possible food or food-additive allergies. All patients underwent single-blind oral challenges to tartrazine (FD&C Yellow 5), potassium metabisulfite, monosodium glutamate, aspartame, sodium benzoate, methyl paraben, butylated hydroxy anisole, butylated hydroxy toluene, FD&C Yellow 6, sodium nitrate, and sodium nitrite. (No effective skin or blood test exists for food additive sensitivity.) Two patients exhibited increases in urticarial skin scores on single-blind tests, but these reactions were not reproducible on subsequent double-blind, placebo-controlled challenges.

Citation(s):

Rajan JP et al. Prevalence of sensitivity to food and drug additives in patients with chronic idiopathic urticarial. J Allergy Clin Immunol Pract 2014 Mar/Apr; 2:168.