Skin blood flow abnormalities in diabetic dermopathy.

Background: Diabetic dermopathy is the most common specific cutaneous finding in diabetes.

Objective: Using laser Doppler technology, we tested the hypothesis that diabetic dermopathy arises from abnormal local skin blood flow.

Methods: We measured cutaneous blood flow in patients with type 1 diabetes without dermopathy and compared values with those in a control group of patients with type 1 diabetes without diabetic dermopathy and in a nondiabetic group. We measured at 3 separate sites on the pretibial area on the legs of each participant, at dermopathy lesions, and at a number of standard sites on the upper and lower extremities.

Results: We studied 25 patients with diabetes and diabetic dermopathy, average age 51 ± 2 years, mean duration of diabetes 28 ± 3 years. In all, 58 patients with type 1 diabetes without diabetic dermopathy served as control patients, average age 41 ± 2 years, mean duration of diabetes 23 ± 2 years. There were 67 nondiabetic control subjects, average age 47 ± 3 years. The patients with diabetic dermopathy showed a marked reduction in skin blood flow at 35°C at normal-appearing skin areas on the pretibial surface of the legs (1.1 ± 0.1 mL/min/100 g) compared with 1.7 ± 0.1 mL/min/100 g (P = .01) in the type 1 diabetic control group and 2.1 ± 0.3 mL/min/100 g (P < .01) in the nondiabetic group. The dermopathy lesions themselves showed markedly higher blood flow: 2.5 ± 0.3 mL/min/100 g.

Limitations: Our diabetic dermopathy patients were somewhat older than the control type 1 diabetes subjects, but were of comparable age to the nondiabetic subjects.

Conclusions: These results suggest that patients susceptible to diabetic dermopathy have a functional abnormality in blood flow leading to this scarring process.