Sweat function in the diabetic foot.

BACKGROUND Autonomic dysfunction, an early manifestation of diabetic neuropathy, presents with altered sweating patterns, leading to dryness and fissuring. We conducted a study to assess the sweat function in the diabetic foot and to determine the interrelation between the duration of diabetes, sensation, fissuring, and sweating. METHODS The sweat function was assessed in 30 diabetic patients, 28 of whom had fissuring of the feet, using Ninhydrin impregnated discs. RESULTS There was a significant association between fissuring and sensation, but not between the duration of diabetes and fissuring and between loss of sweating and fissuring. In 18 patients (60%) there was impairment or absence of sweating in the presence of normal sensation. CONCLUSION Although fissuring increases with long-standing diabetes and sweating is reduced in diabetic patients with fissures on the foot, the correlation between these entities was not statistically significant. Since 60% patients had altered sweating in the presence of normal sensations, the sweat test can be used as an early indicator of diabetic neuropathy.