Clonal mast cell activation syndrome with anaphylaxis to sulfites.

Sulfites are rarely suspected as causative agents of immediate-type hypersensitivity. We report on a 49-year-old male patient who developed recurrent severe hypotension after food ingestion. A diagnosis of monoclonal mast cell activation syndrome was established. In the double-blind, placebo-controlled food challenge, the patient reacted to potassium metabisulfite with anaphylaxis.