Acute parvovirus B19-associated inflammatory musculoskeletal disease: clinical phenotypes and remission trajectories from the GIRRCS Network

OBJECTIVE: To describe clinical phenotype, selected imaging findings and remission trajectories in adults with acute parvovirus B19-associated inflammatory musculoskeletal disease referred for rheumatological assessment. METHODS: This was a non-interventional multicentre observational study in GIRRCS rheumatology units. Adults with new-onset inflammatory musculoskeletal manifestations, positive anti-parvovirus B19 IgM and symptom onset within 4 weeks were enrolled. Clinical, laboratory and clinically indicated imaging data were collected. Time to first documented clinical remission was defined as the interval from symptom onset to the first rheumatologist-confirmed assessment showing resolution of inflammatory musculoskeletal manifestations. Patients requiring disease-modifying escalation were analysed separately. RESULTS: Twenty-four adults were enrolled; 18 were women (75.0%) and mean age was 44.4±14.8 years. Clinical involvement was polyarticular in 14 patients (58.3%) and oligoarticular in 10 (41.7%); enthesitis occurred in 4 (16.7%) and dactylitis was absent. Inflammatory markers were modestly elevated, and most patients with complete autoantibody data were seronegative. Imaging was performed selectively and documented inflammatory abnormalities in clinically indicated examinations. Follow-up data were available for 21 patients, of whom 20 (95.2%) achieved clinical remission without DMARD escalation; median documented remission timing was 21 days (IQR 10-60; range 7-135). One patient required biologic escalation for persistent inflammatory disease. Exploratory regression analyses did not identify robust associations with documented remission timing. CONCLUSION: Acute parvovirus B19-associated inflammatory musculoskeletal disease may mimic inflammatory rheumatic disease in adults referred for rheumatological assessment. Most patients achieved remission without disease-modifying escalation, although remission timing varied and one patient required biologic therapy for persistent inflammatory disease.