Clinical features:
(1) sudden onset of discrete blue or purple areas involving the toes or foot
(2) painful initially, with discomfort decreasing after several days
(3) tender to palpation
(4) lesions darken if the leg is held dependent
(5) signs of ischemia may develop (ulceration to gangrene)
(6) asymmetric if bilateral
Causes:
(1) small atheroemboli (see Section 06.26)
(2) vasculitis
(3) hypercoagulability (including DIC)
(4) hyperviscosity (cryoglobulinemia, macroglobulinemia, other)
(5) cardiac microemboli (often associated with endocarditis or atrial myxomas)
(6) calciphylaxis
(7) corticosteroid-related
(8) cold exposure with vasospasm
(9) following podiatric surgery or trauma
