#2-63E. Parvovirus B19: The Infectious Mimicker Challenging PMR Classification (J Rheum, 2025)

When a patient presents with new-onset bilateral shoulder pain and significant morning stiffness, how confidently do you apply the EULAR/ACR criteria for Polymyalgia Rheumatica (PMR), or do you prioritize ruling out infectious etiologies? Acute Parvovirus B19 (B19V) infection is a recognized mimicker of systemic rheumatic diseases. This letter to the editor evaluated 77 consecutive patients diagnosed with B19V infection, five of whom presented with PMR-like features, including inflammatory pain, prolonged morning stiffness, and elevated acute-phase reactants. The authors applied the non-ultrasound 2012 provisional classification criteria for PMR to this subset. The crucial finding is that the majority (4 out of 5) of these B19V-infected patients fulfilled the classification criteria, suggesting a high potential for misclassification as PMR. This highlights a significant diagnostic pitfall, potentially leading to inappropriate glucocorticoid use. However, a key limitation is the acknowledged lack of imaging studies (such as ultrasound) to confirm or exclude PMR-specific objective findings like bursitis in these patients. This research is highly relevant for clinicians as it underscores the necessity of considering B19V infection in the differential diagnosis of suspected PMR, especially when criteria reliance is high and imaging data is absent.

Citation: Bernardo D’Onofrio, Carlo Selmi. Application of EULAR/ACR Classification Criteria for Polymyalgia Rheumatica in a Series of Patients With Acute Parvovirus B19 Infection. The Journal of Rheumatology. 2025. DOI: 10.3899/jrheum.2024-1024

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