Zusammenfassung
We report the first case of a life-threatening immediate-type hypersensitivity caused by Dynexan(TM), a local anaesthetic gel. After mucosal application by his dentist, a 63-year-old man rapidly developed urticaria, dyspnea and, at last, he collapsed and remained unconscious for 2 hr despite emergency care. While the standard prick tests were negative to all local anaesthetics tested including ...
Zusammenfassung
We report the first case of a life-threatening immediate-type hypersensitivity caused by Dynexan(TM), a local anaesthetic gel. After mucosal application by his dentist, a 63-year-old man rapidly developed urticaria, dyspnea and, at last, he collapsed and remained unconscious for 2 hr despite emergency care. While the standard prick tests were negative to all local anaesthetics tested including lidocaine, a 1-fold positive reaction was detected to Meyprogat 60 (TM), an ingredient of Dynexan(TM). As the gelling agent Meyprogat 60(TM) represents a derivative of guar (synonymous guar gum, guaran, E-412), we subsequently tested different guar products derived from Cyamopsis tetragonoloba beans and, as control, the closely related locust bean gum E-410. In the prick-to-prick tests, the guar-derived food additive Provigel(TM) NAG 905 provoked a 1-fold positive reaction. Native guar beans pounded and resuspended in water showed a 2-fold positive reaction, whereas no reaction was found to derivatives of locust bean gum. Specific immunoglobulin E were negative in all cases. Despite the common use of guar as versatile food additive or gelling agent, this is the first case of a severe immediate-type hypersensitivity after mucosal contact.
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