Parvovirus B19 associated monoarthritis in a 5-year-old boy.

We describe the case of a 5-year-old boy who presented with parvovirus B19 associated arthritis of the left knee lasting for 6 weeks. Other features included flu-like symptoms, a mild "slapped cheek" sign, and a macular, erythematous, lace-like rash over the chest and limbs. The analysis of the synovial fluid showed a high white cell count with a predominance of polymorphonuclear cells. The characteristic features related to parvovirus B19 associated arthropathy in children are reviewed.