An acute blue finger is an uncommon but potentially serious finding with a 
heterogeneous etiology. A rare group of patients will present with acute, 
atraumatic, nonischemic blue fingers. The clinical course of these patients 
appears to be benign. We describe the presentation of an otherwise healthy 
22-year-old woman with an acute idiopathic blue finger. We highlight the 
differential diagnoses and evaluation of this rare condition.