There are numerous disorders that can mimic vasculitis clinically. When cutaneous vasculitis is suspected, the first step in
management should be to confirm the diagnosis by skin biopsy. Geographic areas of purpura with necrosis and ulceration can be due to
antiphospholipid antibody syndrome, recognized histologically by noninflammatory small vessel thrombi (left-sided panels) or small vessel
neutrophilic vasculitis, identified histologically by the findings of vessel wall fibrin deposits, perivascular nuclear debris, and disruption of
the vessel wall by the neutrophilic infiltrate (right-sided panels).

J. Andrew Carlson, MDa,b,*, L. Frank Cavaliere, MDc, Jane M. Grant-Kels, MDdCutaneous vasculitis: diagnosis and management Clinics in Dermatology (2006) 24, 414– 429