All are true about the features of erythromelalgia , EXCEPT:
Unknown aetiology
Thrombocytosis is seen
Digital infarction is seen
Treatment is steroids
Erythromelalgia Syndrome of unknown etiology It is associated with thrombocytosis Manifested by erythema, warmth, and pain of the affected appendage and occasionally digital infarction. It usually respond to salicylates. Ref: Harrison, E-18,P-903