Human parvovirus B19 (B19V) causes a number of skin exanthemas and has been related to both cutaneous and systemic diseases. Tropism of the virus for the rapidly proliferating erythroid progenitor cells in the bone marrow and fetal liver explains the pathogenesis of anemia and fetal hydrops. The cutaneous lesions of erythema infectiosum and other B19V-related exanthemas have been attributed to the deposition of immune complexes in the skin. We report on the immunohistochemical detection of B19V protein in the cytoplasm of dermal endothelial cells in a case of periflexural exanthema in a 28-year-old woman. An antibody-dependent enhancement mechanism of entry has been suggested for B19V in myocardial endothelial cells and could also be involved in B19V-related exanthemas.