"Cold Hands" Sign
In multiple system atrophy (MSA), the hands may be cold, dusky, and violaceous with poor circulatory return after blanching by pressure, suggesting defective neurovascular control of the distal extremities as one feature of the autonomic dysfunction in MSA. The findings are not present in idiopathic Parkinson’s disease.
Klein C, Brown R, Wenning G, Quinn N. The "cold hands sign" in multiple system atrophy. Movement Disorders 1997; 12: 514-518