Parvovirus B19 infection with rheumatologic manifestations: results from a multicentre Italian study

Objectives: To characterise the clinical spectrum of adult parvovirus B19 (B19V) infection referred for rheumatologic evaluation and to identify clinical predictors of arthritis resolution. Methods: We conducted a multicentre retrospective study across nine Italian rheumatology units during the 2023-2024 post-pandemic resurgence of B19V infection. Clinical, therapeutic, and follow-up data were systematically collected using a standardised REDCap platform. Results: We enrolled 71 patients (median age 43 years; 72% female), 85% with a confirmed diagnosis. Most reported recent household exposure. Joint involvement was nearly universal (96%), predominantly oligoarticular, and often affected large joints, mimicking early inflammatory arthritis. Fever (65%) and skin manifestations (61%) were frequent. In addition to typical exanthems, 9 patients displayed a distinctive purpuric rash confined to the pretibial region, sparing ankles and feet - a potentially distinctive feature of to B19V infection. Symptom resolution occurred in 87% of cases, usually within one month. Glucocorticoid use was independently associated with - but not proven to cause - faster resolution in Cox regression (HR 0.53; 95% CI: 0.31-0.90; p=0.020), though this finding may reflect indication bias. No other clinical or serological predictors emerged. Conclusions: This study provides the largest systematically collected multicentre cohort of adults with B19V infection referred to rheumatology during the post-pandemic European outbreak. Our findings expand the clinical spectrum of B19V arthritis and highlight distinctive skin patterns that may aid differential diagnosis during epidemic waves.