Cutaneous Vasculitis as a Manifestation of Oropouche Fever: Case Report

To the Editors: We present the case of a 10-year-old girl with rheumatoid factor-positive polyarticular juvenile idiopathic arthritis who was on methotrexate therapy. She initially presented with fever and polyarthritis affecting the hands, knees and ankles, accompanied by prostration, abdominal pain, nausea, vomiting, pleuritic chest pain, anasarca and progressive thrombocytopenia (nadir platelet count: 15,000/mm³). Subsequently, pruritic purpuric lesions developed, prompting skin biopsy. Laboratory evaluation revealed normal complement levels (C3 and C4) and unremarkable urinary sediment. Despite administration of broad-spectrum antibiotics, her symptoms persisted. Polymerase chain reaction testing for arboviruses (dengue, chikungunya, Zika and OROV) was positive for OROV. The patient was treated with intravenous immunoglobulin (1 g/kg), which significantly improved clinical symptoms and laboratory parameters. Histopathological analysis of the skin biopsy specimen revealed leukocytoclastic vasculitis with negative direct immunofluorescence (IF) findings (Figs. 1 and 2).FIGURE 1.: Leukocytoclastic vasculitis (H&E staining, 40× – original magnification). Normal epidermis is observed with perivascular inflammatory infiltrate in the dermis.FIGURE 2.: Leukocytoclastic vasculitis (H&E staining, 400× – original magnification). An inflammatory infiltrate with a predominance of lymphocytes and neutrophils is observed around small vessels, associated with leukocytoclasia, necrosis with perivascular fibrin depositions and the presence of erythrocytes.The absence of immunoglobulin or complement deposition on biopsy suggests a direct viral mechanism underlying vasculitis, distinguishing it from IgA-mediated processes, which typically present as postinfectious vasculitis with positive IF findings. This highlights a novel pathophysiological mechanism of OROV-associated vasculitis that is distinct from other immune-mediated processes. Approximately 1 week later, the patient experienced recurrence of polyarthritis, vasculitic lesions and pleuritic chest pain. Chest computed tomography revealed atelectasis, while echocardiographic and electrocardiographic evaluations were normal. This biphasic pattern aligns with previously described presentations of OROV infection, which often include a second wave of symptoms occurring 1 week after the initial recovery.1–4 Although viral infections are known to trigger vasculitic processes,2 this report represents the first documented case of leukocytoclastic vasculitis associated with an OROV infection. Early molecular diagnostic testing, along with IF staining, is crucial in confirming the viral etiology and differentiating it from other infectious or autoimmune causes. This case emphasizes the importance of considering OROV in the differential diagnosis of pediatric vasculitis, particularly in endemic regions and among immunocompromised patients. Severe systemic manifestations, including thrombocytopenia, abdominal pain and pleuritic chest pain, may complicate the clinical course.5 Recognizing viral infections as potential triggers of vasculitis broadens the diagnostic framework for complex clinical presentations in pediatric practice.