FUNCTIONAL-STUDY OF THE DERMAL MICROCIRCULATION IN SYSTEMIC-SCLEROSIS

To measure the effect of cooling on digital blood pressure we used a s train-gauge and photopletysmograph, with an automatic cooling device. Eighteen patients were compared with 18 matched controls. Laser-dopple r technique was used to measure the perfusion changes after heating a small area of the skin in 5 locations on the body, readings were given in perfusion units. Eighteen patients with systemic sclerosis were co mpared with 25 individuals with primary Raynaud's phenomenon and 30 he althy controls. Cooling to 10 degrees C caused a significant digital b lood pressure drop of 58 mm Hg in patients with systemic sclerosis and 61 mm Hg in Raynaud's phenomenon, as compared with controls. The micr ocirculation in patients with systemic sclerosis responded in the same way to local heating as in the normal population, increasing the perf usion to the same extent. In conclusion, an unselected group of patien ts with systemic sclerosis have normal dermal microcirculatory respons e to heating in spite of severe cold intolerance.