Hardness of plantar skin in diabetic neuropathic feet

To evaluate if skin hardness in diabetic neuropathic feet was increased and if its eventual modifications could be correlated to the severity of neuro pathy, we studied a group of diabetic outpatients with and without neuropat hy. Patients, selected among those who were attending their routine screeni ng for diabetic neuropathy at our diabetologic clinic, were divided into tw o groups according to the presence (ND+) or absence (ND-) of diabetic neuro pathy with the criteria of the S. Antonio Consensus Conference on Diabetic Neuropathy. Patients then underwent an evaluation of vibration perception t hreshold (VPT) by means of a biotesiometer, measurement of skin hardness (D MT) by means of a durometer, and transcutaneous oxygen tension (TcPO2) dete rmination. VPT was determined at allux (VPT-A) and external malleolus (VPT- M), DMT was measured at heel (DMT-H), at medial (DMT-M) and lateral (DMT-L) midfoot, and at posterior midcalf (DTM-C) as a control site; TcPO2 was eva luated at dorsum (TcPO2-D) and at medial midfoot (TcPO2-M), respectively. A ll measurements were performed on the nondominant side with the patients su pine. Patients were compared with age and gender-matched healthy volunteers (Controls), who underwent the same evaluations in the same order. ND+ pati ents showed higher values of VPT than ND- and Controls, both at first toe a nd at malleolus analysis of variance (ANOVA, p < 0.01), as well of DMT in a ll the three sites explored (ANOVA, p < 0.01). Moreover, ND+ showed no diff erence in DMT among the sites, while both in ND- and in controls DMT-M was significantly (p < 0.05) lower than DMT-H and DMT-L. No difference among th e three groups were observed in TcPO2 measurements, and no difference in DM T-C was observed either. A significant correlation was observed between DMT -H and VPT-M (r(2) = 0.516) and between DMT-M and VPT-A (r(2) = 0.624) in N D+ patients. Skin hardness was diffusely increased in ND+ patients, and thi s increase strongly correlates with the severity of neuropathy. Simple, non invasive determination of skin hardness could identify patient at potential risk to develop neuropathic foot ulcers. (C) 1999 Elsevier Science Inc.