# Parvovirus B19 in Children: Clinical Spectrum, Viral Load Patterns, and Atypical Cutaneous Presentations in the Post-Pandemic Outbreak

## TL;DR

This study examines how parvovirus B19 affects children, focusing on symptoms, viral load, and unusual skin rashes during a recent outbreak in Europe.

## Contribution

The study identifies higher viral loads as a predictor of atypical cutaneous presentations in children with parvovirus B19.

## Key findings

- Higher viral load was associated with petechial rash in infected children.
- Patients with petechial rash were older and had lower platelet counts.
- Viral load was the only independent predictor of atypical rash in multivariate analysis.

## Abstract

Background: Human parvovirus B19 causes a broad spectrum of clinical manifestations, ranging from the classic “fifth disease” to severe presentations. Clinical presentation varies considerably across age groups. In 2023–2024, a notable increase in parvovirus B19 cases was reported across Europe. Methods: We retrospectively analyzed pediatric patients with serum serology and/or plasma PCR-confirmed parvovirus B19 infection treated at the tertiary infectious diseases center (University Hospital for Infectious Diseases, Zagreb) in 2023 (January–August). Demographic, laboratory, viral load, and clinical characteristics were assessed, with emphasis on cutaneous manifestations. Results: A total of 102 patients were included (median age 10 years; 54.9% male), of whom 7.8% required hospitalization. Rash was present in 94 (92.2%) of the patients of whom 75 had erythema infectiosum and petechiae, while the rest had a combination of both. Patients with petechial rash were significantly older (p = 0.013) and exhibited lower platelet counts (p < 0.001) compared with those with erythema. A higher proportion of anti-B19V IgM (p = 0.027) and IgG (p < 0.001) antibodies was detected in patients with erythema. Petechial rash was associated with higher viral loads (p < 0.001). In univariate analysis, the presence of anti-B19V IgG antibodies was correlated with the absence of petechial rash (OR = 0.09; p < 0.001), whereas higher viral load was associated with its presence (OR = 1.7; p < 0.001). In multivariate analysis, viral load emerged as the only predictor of petechial rash (aOR = 1.4, p = 0.042). Conclusions: Parvovirus B19 remains a self-limiting illness in healthy children, despite frequent atypical presentations. Higher viremia is associated with atypical rash morphology and suggests age-related differences in immune clearance.