A 35-year-old Caucasian man was referred for evaluation of recurrent upper extremity digital ischemia. He had experienced three discrete episodes of acute right finger discoloration over the previous 2 years. The first episode involved a spontaneous, painless purple mass that appeared at the base of the right fourth finger without antecedent trauma. A two-dimensional transthoracic echocardiogram (TTE) performed to assess for a cardiogenic source of emboli was normal. The finger discoloration resolved within several days. Computed tomographic angiography (CTA) of the aortic arch and left upper extremity arteries was performed and was normal. He was ultimately diagnosed with benign blue finger.
ETIOLOGY AND PATHOPHYSIOLOGY
The pathophysiology of BABF is unrecognized.
A mechanism of subcutaneous ecchymosis due to spontaneous rupture of a small digital venule has been suggested1 and this syndrome has been referred to as "spontaneous venous hemorrhage."
The diagnosis of BABF is clinical. A comprehensive history and physical examination must be performed to exclude other potential etiologies, as this is a diagnosis of exclusion.
A thorough history should be obtained from any patient presenting with an acute blue finger. The history should be aimed at risk factors for cardiogenic sources of emboli (eg, prior myocardial infarction, atrial fibrillation, valvular heart disease), atherosclerotic risk factors, thoracic outlet syndrome, or toxin ingestion (cocaine, methamphetamines [ie, Adderall], ergotamines). History suggestive of rheumatologic diseases should be pursued.
BABF is often isolated to one finger (Figures 57-2 and 57-3). It may recur in different locations.2,3
An important, yet not mandatory (Figure 57-4), physical finding is sparing of bluish discoloration of the fingertip. Physical examination must not reveal embolic phenomena.4
Purple-blue discoloration of the palmar surface of the third digit on the right hand. Notice the tip of the finger is not involved. (Photograph courtesy of Dr. Bruce Mintz.)
Acute benign blue finger involving the right third digit. The patient was initially misdiagnosed with Raynaud phenomenon. (Photograph courtesy of Dr. Bruce Mintz.)
Diffuse palpably warm cyanotic right third finger is displayed in a classic representation of acute benign blue finger. (Photograph courtesy of Dr. Bruce Mintz.)
Purplish discoloration along the distal portion of the finger illustrating an exception to the rule in this case of acute benign blue finger. (Photograph courtesy of Dr. Bruce Gray.)