Metabisulfite challenge in patients with idiopathic anaphylaxis.

Bronchospasm, urticaria, angioedema, and anaphylactoid reactions have been attributed to sulfiting agents. These compounds are commonly used as preservatives in some drugs and foods, often in restaurants. Oral challenges with sodium metabisulfite were performed in 12 patients with idiopathic anaphylaxis (IA). Nine of these had episodes possibly caused by sodium metabisulfite because of clear temporal relation of episodes of IA to restaurant meals. One patient who had severe urticaria with exacerbations with restaurant meals and 10 control subjects were studied. No urticarial, asthmatic, or anaphylactoid reactions occurred in our patients. Sulfiting agents did not trigger episodes of IA in these 12 patients or urticaria in the patient with severe chronic idiopathic urticaria.