A One-Year-Old Girl With Human Parvovirus B19 Infection and Hypocomplementemia Mimicking Incomplete Kawasaki Disease.

Human parvovirus B19 (B19) is a single-stranded DNA virus that targets erythroid progenitor cells in the bone marrow. B19 causes erythema infectiosum in children, transient aplastic anemia, pure red cell aplasia, hydrops fetalis, and contributes to other illnesses. An association between B19 infection and hypocomplementemia and rheumatoid arthritis has been reported, but the underlying mechanisms remain unclear. We report the case of a 1-year-old Japanese girl with persistent fever, skin rash, transient edema of the extremities, hypoalbuminemia, and hypocomplementemia associated with B19 infection. We considered Kawasaki disease (KD) and collagen diseases, particularly systemic lupus erythematosus, in our differential diagnosis. B19 infection might be associated with serological features that suggest systemic lupus erythematosus and may present with clinical symptoms seen in KD. Especially during erythema infectiosum epidemics, we must consider B19 infection in the differential diagnosis of KD patients who demonstrate atypical clinical symptoms and unexplained laboratory findings.