Necrosis of the external ear (auricle) can occur in a number of conditions.
Patient selection: focal or diffuse necrosis of the external ear
Differential diagnosis:
(1) cold agglutinin disease
(2) spider or snake bite
(3) embolic therapy of intracranial arteriovenous malformation
(4) trauma to the ear
(5) systemic thrombotic disorder
(5a) antiphospholipid syndrome
(5b) heparin-induced thrombocytopenia
(5c) severe vasculitis
