Facial and sublingual temperature changes following intravenous glucose injection in diabetics

Facial and sublingual temperatures were measured in 61 diabetics undergoing intravenous glucose tolerance tests. Within 2 minutes of starting glucose injection, 58 patients felt warm in the face and trunk, 56 showed a rise in cheek temperature and 23 had visible facial reddening. The most important determinant of cheek temperature rise was initial cheek temperature. Cheek temperature rise was a unimodally distributed variable and was significantly larger in patients with fasting plasma glucose greater than or equal to 6.1 mmol/l than in those with lower glucose (despite similar initial cheek temperatures). Initial cheek temperature correlated with ambient temperature in men with fasting glucose greater than or equal to 6.1 mmol/l but not in those with fasting glucose less than or equal to 6.0 mmol/l nor in women. Initial tongue temperature was also related to ambient temperature in men but not in women and fell following the glucose injection. Although the glucose flush differs from the the chlorpropamide-alcohol flush in its unimodal distribution and relatively small temperature rise, some of the factors which influence reaction could well be considered with benefit in analysis of the chlorpropamide-alcohol flush, in particular the initial cheek (and ambient) temperatures, sex and fasting plasma glucose concentration.