Purpura hemorrhagica, although rare, is
an acute inflammation of blood vessels and capillaries (vasculitis) that occurs as a result of an immune reaction to the S. equi proteins.
Pediatric rheumatic diseases (PRDs) are chronic multisystem disorders, involving
acute and chronic tissue
inflammation of the musculoskeletal system,
blood vessels, and skin (Cassidy & Petty, 1995).