Pathophysiology of Roseola Infantum When HHV-6 enters the body, it binds with upper respiratory tract where it undergoes replication in the epithelial cells. Soon, virus invades the subepithelial tissue. After rapid replication, it spreads into body by hematogenous and lymphoid routes. This is followed by viremia. Virus infects the endothelial cells of blood vessels in the skin leading to the formation of maculopapular rashes on skin.