[Transcutaneous measurement of oxygen and carbon dioxide pressure in necrobiosis lipoidica].

Transcutaneous measurement of oxygen pressure (PcO2) and carbon dioxide pressure (PcCO2) was performed in nine patients with histologically confirmed necrobiosis lipoidica. None of the patients had diabetes mellitus. All measurements were taken at the lower leg. In each case, the atrophic center, the inflamed border, and the surrounding clinically normal skin of necrobiosis lipoidica were examined at 44 degrees C sensor temperature (maximal vasodilatation). Statistically significant hypoxia was found in the area of necrobiosis lipoidica, which was even more pronounced in the inflamed border. Inhalation of 100% oxygen provoked a marked increase in the PcO2 in the lesion, but the values were still significantly lower than in the normal skin. At the edge of the lesions the PcCO2 was significantly elevated. These findings support a vascular origin of necrobiosis lipoidica, involving reduced vascular perfusion combined with diffusion block.