Anaphylactic reaction after a scratch test with ascorbic acid (E 300) and citric acid (E 330)

We report the case of a 62-year-old man with frequent angioneurotic edema a nd systemic reactions, who showed a positive scratch test with ascorbic aci d and citric acid. Twenty minutes after testing he developed an angioneurot ic edema with glottis swelling, reddening of face and hands, with itching, vertigo, tachycardia and decrease of blood pressure. Both substances are us ed as food additives; ascorbic acid (E 300) is used as an acidifying, antio xidant substance and as additive in wheat, citric acid (E 330) is used as a n acidifying and complex-binding substance. Because additives are widely us ed in foods, beverages and drugs, persons with sensibilization or intoleran ce have to be instructed very well. As shown in our case, caution has to be taken also when scratch tests with these substances are performed. Also, m edication given in case of emergency can contain additives which the patien t doesn't tolerate.