The "cold hands sign" in multiple system atrophy.

Patients with multiple system atrophy (MSA) often have cold, dusky, violaceous hands, with poor circulatory return after blanching by pressure. We therefore compared hand skin temperature in nine age-matched subjects with probable MSA, 10 with idiopathic Parkinson's disease (PD), and 10 healthy controls both at rest and following a standard cooling procedure. Baseline skin temperature in the MSA group was significantly lower than in both the PD and control groups, and four of the nine MSA patients were colder at baseline than the coldest control value. After cooling, the MSA group also showed a significantly greater reduction in skin temperature than the PD group. The rate of skin temperature recovery did not differ between the three groups, although the MSA group required more time to return completely to their baseline temperature. Changes in skin colour or temperature are easily detected, and suggest a defect in neurovascular control of distal extremities. The "cold hands sign" is another clinical "red flag" that helps to raise the suspicion of MSA.