mononeuritis multiplex

Most systemic diseases associated with mononeuritis multiplex, including vasculitides, connective-tissue disease, cryoglobulinemia, sarcoidosis, diabetes, amyloidosis, neoplasms, and infections, cause nerve damage by affecting the vasa nervorum.

http://content.nejm.org/cgi/content/full/360/7/711

Livedoid Vasculopathy

Livedoid vasculopathy is a segmental, hyalinizing vasculopathy that involves small and medium-sized blood vessels in the lower legs. It can present with livedo changes in the skin, focal purpura, and painful, irregularly shaped lesions around the malleoli. It can be an isolated or a primary condition or can be associated with a variety of hypercoagulable risk factors, including antiphospholipid antibodies, as well as most other serologic and genetic risk factors for either venous or arterial thromboses, and connective-tissue diseases.20 Our patient's cutaneous findings could be explained by livedoid vasculopathy occurring in the setting of a connective-tissue disorder, the most likely of which would be SLE.