Allergic purpura, also known as purpura, is an allergic vasculitis that invades the fine arteries and capillaries of the skin and other organs. It may be caused by allergy to drugs or infectious agents, leading to autoimmune changes in the body, resulting in deposits in the epithelium of the blood vessels and manifesting as vasculitis. It manifests as purpura on the skin and can also manifest as renal vasculopathy, manifesting as purpura nephritis. This can be accompanied by hematuria and proteinuria. Routine urinalysis is performed, which reveals an elevated number of red blood cells, along with the presence of protein in the urine, and is accompanied by changes such as renal failure and elevated blood pressure. Anti-allergic treatment and immunological therapy are required to prevent progressive renal impairment. It can also manifest as an arthritic and cutaneous form, which can present as allergic purpura on the skin and can lead to changes such as joint pain and effusion in the joint cavity.