Renal involvement can lead to glomerulonephritis and hypertension, which are leading causes of morbidity and mortality. Approximately 25 percent of cases of classic polyarteritis nodosa will have cutaneous involvement. The most common cutaneous presentations include nodules, ulcers, and a livedo reticularis pattern on the lower extremities. The nodules are usually deep and painful, and may occur on the trunk and upper extremities. Benign cutaneous polyarteritis nodosa is a disease that is limited to the skin, muscles, and joints.
Nodules are more common in the cutaneous variant.
Four cases have been reported in which there was progression from cutaneous polyarteritis nodosa to systemic polyarteritis nodosa. In a study of 38 patients observed for up to 27 years with cutaneous polyarteritis nodosa, none developed systemic involvement. The cause of both forms of polyarteritis nodosa is unknown, but an autoimmune etiology has been proposed. This is supported by direct immunofluorescence studies, which show immune complex deposits of IgM, C3, and fibrin. Polyarteritis nodosa has been associated with hepatitis B virus, hepatitis C virus, Crohn's disease, Takayasu's arteritis, relapsing polychronditis, streptococcal infections, and tuberculosis.