Development of Arthritis as the Initial Involvement in Adult-Onset Cutaneous Polyarteritis Nodosa: Two Cases and Literature Review.

Articular symptoms are commonly present in polyarteritis nodosa (PAN). Meanwhile, they may occur as the initial and main involvement of PAN, raising a concern of a delay in a definitive diagnosis of disease unless the histological evidence is obtained. Herein, we report two cases of cutaneous PAN (c-PAN) in which arthritis developed as the initial clinical episode of disease and we argued, through a review of the literature, the clinical feature of patients presenting with arthritis as the initial symptom of PAN. To our knowledge, only six cases have been reported in the English literature, and all six patients were categorized as having c-PAN. Of those patients, four had arthritis with indicating destructive changes. A median of 9 years elapsed prior to the induction of immunosuppressive treatment despite the fact that the other reviewed cases as well as our two patients, who received treatment significantly earlier, showed no evidence of joint destruction. Taken together, this report suggests that the early induction of therapy based on the definitive diagnosis of PAN may be required for preventing joint disruption even though it is not easy to make a diagnosis of PAN unless biopsied tissue can provide the evidence of necrotizing vasculitis.