Anaphylactic shock after intra-articular injection of carboxymethylcellulose

Background: sodium carboxymethylcellulose (SCMC) is the sodium salt of a polycarboxymethyl ether of cellulose. SCMC is widely used in pharmaceutical and food industries. We present the case of a 47-year-old man who suffered an anaphylactic shock after an intra-articular injection of Trigon depot®. Methods and results: prick and intradermal tests with Trigon depot® and its components (triamcinolone acetonide, Tween 80, benzylalcohol, SCMC), mepivacaine 2% and latex were performed. Challenge test with mepivacaine 2% was also realized. Results showed a positive intradermal test to Trigon depot® and carboxymethylcellulose, with negative results to the rest (including challenge test to mepivcaine 2%). Conclusions: our results support the diagnosis of anaphylactic shock after intra-articular injection of carboxymethylcellulose and we consider necessary to emphasize that excipients must be taken into account as a potential source of adverse reactions to drugs.