[Cutaneous microcirculation in pretibial necrobiosis lipoidica. Comparative laser Doppler flowmetry and oxygen partial pressure determinations in patients and healthy probands].

Necrobiosis lipoidica (NL) is a chronic, skin disease usually localized pretibially and often associated with diabetes mellitus. Primary vascular disturbances are considered pathogenetic for NL. In order to determine microcirculatory alterations in "idiopathic" NL linked with neither arterial hypertension nor diabetes mellitus, we performed simultaneous measurements of laser-Doppler flux (LDF) and oxygen tension (pcuO2) in 10 non-diabetic patients with NL and in 10 age- and sex-matched healthy volunteers. We examined the centre of the pretibial NL plaque, its border and the non-affected skin of the proximal lower leg at probe temperatures of 36 degrees C (flux) and 37 degrees C (pcuO2). Corresponding sites and temperatures were chosen for the controls. In addition, the degrees of hyperaemia caused by arterial occlusion (3 min) and during local heating (42 degrees C) were continuously measured. The initial pcuO2 values were found to be lowered, in contrast to increased fluxes within and around the NL lesions. In addition, responses of both flux and pcuO2 to the hyperaemic stimuli were weaker than in the corresponding skin of the healthy controls. Only minor differences from controls or none at all were found in clinically unaffected lower leg skin of the patients. Our results indicate a local alteration of microcirculation in patients with "idiopathic" NL that occurs independently of diabetes.