Multiple Mononeuropathy Secondary to Parvovirus B19 Infection: A Case Series

Background Parvovirus B19 (B19V) infection has been associated with neurological complications. Rarely, patients present with multiple mononeuropathy (MM). The present study aimed to better characterize the clinical, electrophysiological, and prognostic features of patients with B19V‐related MM. Methods This retrospective, observational, multicenter study included patients with B19V‐related MM diagnosed between January 2015 and January 2025 in seven university hospitals in France and Switzerland. Results Twenty‐one patients were included. Twelve were female (57%). All were immunocompetent. The median age at symptom onset was 40 years [IQR: 31–44]. All patients experienced sensory symptoms, 19 (90%) reported neuropathic pain, nine (43%) developed motor weakness, and seven (33%) had cranial nerve involvement. The most frequently involved nerves were the median (14 patients, 67%), fibular ( n = 13; 62%), and ulnar ( n = 10; 48%) nerves. B19V IgM antibodies were present in 12/20 patients (60%), and all 21 patients were positive for IgG. B19V DNA was detected in blood by PCR in 20 patients (95%). Nerve biopsy showed necrotizing small‐vessel vasculitis in one patient (17%), perivascular lymphocytic and macrophagic infiltrates in five (83%), and B19V DNA was detected by PCR in all four tested nerves. Most patients received immunomodulatory treatment ( n = 19; 90%). MM relapse occurred in four patients (19%). A partial recovery was observed in 17/20 patients (85%), two remained stable (10%), and one achieved complete recovery (5%). Conclusions B19V infection should be systematically investigated in patients presenting with MM, especially in young individuals (including children) with predominantly sensory symptoms, predominant upper limb nerve involvement, and/or cranial nerve involvement.