Previous reports have demonstrated that patients with confirmed IgE-mediated anaphylaxis to carboxymethylcellulose, triggered by triamcinolone acetonide injections, tolerated oral administration of trimethoprim-sulfamethoxazole (which contains small amounts of CMC) as well as oral provocation with typical dietary and pharmaceutical doses of CMC, suggesting an absence of clinically relevant reactivity via the oral route (1, 6, 7). This evidence concerns the gene IGHE and anaphylaxis.