FRI0286 CUTANEOUS POLYARTERITIS NODOSA: A SUBSET OF SYSTEMIC PAN OR A DISEASE APART?

Abstract

Background Cutaneous Polyarteritis Nodosa (cutaneous PAN) is a rare form of necrotizing vasculitis involving predominantly medium and small arteries. It is limited to the skin. The clinical course is mostly chronic, however it has a more favourable prognosis than systemic PAN. Cutaneous PAN may be preceded by infection, drugs intake or may reflect underlying inflammatory or autoimmune disease. The diagnostic criteria are controversial and in some cases overlapping with those of systemic PAN. Cutaneous PAN is limited to the skin, but occasionally patients present extracutaneous symptoms, namely: myalgia, arthralgia or multineuritis Objectives To describe the clinical manifestations of cutaneous PAN, emphasizing the extracutaneous manifestations, as well as comorbid associations. Methods Retrospective study (1989-2018) of patients with cutaneous PAN seen in a tertiary center: referral area 800.000 inhabitants. All the cases were reviewed regarding epidemiological, clinical, electromyographic, histopathological and laboratory findings. Infections and comorbid diseases were also reviewed. Results Twenty-three cases were recruited: 8 male (34.78%) and 15 female (65.22%) patients. Mean age at onset: 47 years (range 18-76). Mean follow-up period :105 months (range 12-380). Cutaneous manifestations included: subcutaneous nodules (95.65%), ulcers (52.17%), livedo reticularis (60.87%), livedo racemosa (8.70%), atrophie blanche (39.13%) and purpura (4.34%). Cutaneous PAN most commonly occurred on the legs (100%), followed by the thighs (47.83%), the upper limbs (39.13%) and the trunk (17.39%). The most frequent extracutaneous symptom were asthenia (78.26%). Extracutaneous manifestations, limited to the same area of cutaneous lesions, were myalgia (60.87%) and paraesthesia (56.52%). An electromyography was performed in 14/23 patients and mononeuritis multiplex was observed in 7 patients. Only one patient progressed to systemic PAN, with development of renal disease 12 month after the diagnosis. The following infections were identified: hepatitis C (2), tuberculosis (1), Streptococcus pyogenes (1) and rickettsia (1). Comorbid diseases included: autoimmune hypothyroidism (2), cutaneous psoriasis (1), recidivant polychondritis (1), adult onset Still’s disease (1), ulcerative colitis (1), pulmonary idiopathic fibrosis (1) and acute myeloid leukaemia (1). Glucocorticoids were used at medium-high doses (20-40 mg/day) in 20 patients as induction therapy, and NSAIDs at full doses in the remaining 3. Thirteen patients (56.52%) developed relapsing forms. Of this, 12 patients (52%) needed associated immunosuppressive treatment to prevent relapse. The most widely used immunosuppressant was methotrexate, followed by mycophenolate or azathioprine. Conclusion A long-term follow-up, with careful anamnesis and examination, including electromyography, is necessary to better characterize the cutaneous and extracutaneous manifestations of cutaneous PAN. The progression to systemic involvement is infrequent and cutaneous PAN has a more benign course from a clinical, and prognostic point of view.