Allergic purpura is mainly seen in adolescents and children, with a higher incidence in spring and autumn. The most common cause is infection, followed by medications or food, which can also trigger an episode of allergic purpura. The most common symptoms include purpura on the skin and mucous membranes, abdominal pain, blood in stools, hematuria, or joint pain. The purpura primarily affects the limbs, rarely appears on the trunk, and is symmetrically distributed. At this time, the bleeding spots often have no symptoms, meaning there is no itching of the skin. However, when there is concomitant skin edema or hives, itching can occur.