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We report the first case of a life-threatening immediate-type hypersensitivity caused by Dynexan, 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, an ingredient of Dynexan. As the gelling agent Meyprogat 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 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.

In a randomized, double-blind, controlled clinical study, the effects of 5 g of guar gum, a dietary fiber composed of galactose and mannose, or placebo added to the diet of 20 patients with duodenal ulcer for 1 wk each were examined. Ten patients derived evident benefit and five some help from guar gum, on comparing symptoms during administration of guar gum with those experienced earlier or during the placebo week, whereas four patients found that neither guar gum nor placebo had any effect (p less than 0.001). The beneficial effect was associated with increased feelings of repletion after meals. Patients with fewest symptoms benefited only slightly, or not at all, from guar gum. In one patient, guar gum abolished pain felt earlier and on placebo, but also caused severe gastric retention after meals. This patient had pyloric stenosis. In patients who were intolerant to berries, fruits, sugar, sweet rolls, and pizza these foodstuffs were better tolerated during guar gum administration. The diarrhea which occurs in some patients ingesting guar gum was avoided by giving low initial doses. In three patients unpalatability of guar gum was a minor complaint. It is concluded that guar gum is helpful to many patients with uncomplicated duodenal ulcer, but that it is harmful to those having increased gastric emptying, eg, pyloric stenosis patients, and that guar gum may exert its effects by increasing gastric emptying time.

The occurrence of dumping symptoms during 1 wk of use of 5 g of guar gum or placebo in meals was examined in a double-blind study in 11 patients, who had undergone gastric resection and were suffering from the dumping syndrome. The results show that guar gum prevented the dumping syndrome and increased tolerance to foods not previously tolerated in nine of the 11 patients.