4.Erythema nodosum - venulitis with panniculitis. Tender, warm, erythematous nodules over lower extremities. Often associated with underlying illness. Diagnosis and evaluation of patients with vasculitis. A. Making diagnosis.
Laboratory tests are usually of minimal diagnosis because they are usually nonspecific.
ANA is usually negative. RF is positive in essential mixed cryoglobulinemia and sometimes Wegener' s granulomatosis. Immune complexes and complement studies show evidence of immune complex disease. Aortic arch - Takayasu's arteritis. Determine extent of disease.