Allergic reaction to sulfiting agents.

Sodium metabisulfite (MBS) is a commonly used food and drug preservative. We report the case of a 32-year-old man with a documented history of allergy to MBS who developed an anaphylactic reaction after ingestion of MBS-treated foods. The patient had a prolonged clinical course requiring two emergency department visits and three weeks of outpatient steroid therapy. It is believed that this patient's relapse and delayed recovery may have been related to his continued exposure to sulfites during treatment. The emergency physician should be aware that some medications commonly used to treat allergic reactions and asthma contain MBS.