Clinical and laboratory findings characterizing the need for systemic corticosteroids and nonsteroidal systemic therapies and the predicted outcomes in cutaneous polyarteritis nodosa: a single-centre retrospective analysis.

Background: Cutaneous polyarteritis nodosa (cPN) is a necrotizing arteritis of medium-sized vessels limited to the skin. Because of its rarity and the diversity of its clinical manifestations, there is no consensus treatment. Moreover, there are no established indicators that predict disease severity or its outcome.

Objectives: To investigate clinicolaboratory features that predict patients requiring systemic therapy, including corticosteroids, to control disease activity.

Methods: Thirty-six patients with cPN who had not received systemic corticosteroids at their initial visit were retrospectively analysed by correlating the treatment and its response with clinicolaboratory findings.

Results: The major medications administered were antiplatelet agents [64% (23/36)], vasodilators [39% (14/36)] and prednisolone (PSL) [36% (13/36)]. In total, 23 patients achieved remission without PSL, 5 were managed with compression therapy alone or even observation and 18 received antiplatelet monotherapy or combined with vasodilator/dapsone whereas 13 required PSL. Of the 13 who required PSL, 10 achieved remission with PSL monotherapy or PSL and single/multiple medications and 3 with PSL and multiple drugs then failed to achieve remission and underwent limb amputation. There were more skin ulcers and an elevated peripheral white blood cell (WBC) count and erythrocyte sedimentation rate (ESR) before corticosteroid induction in patients requiring PSL. Three patients with treatment failure had a markedly elevated ESR (> 50 mm h-1).

Conclusions: More than half of patients with cPN can achieve remission without corticosteroids. An elevated WBC, an elevated ESR and the presence of skin ulcers predict the need for PSL. A high ESR before corticosteroid induction predicts treatment resistance, even with PSL.