Anaphylactic purpura is an IgA-type antibody-mediated allergic capillary and small vessel vasculitis characterized by nonthrombocytopenic cutaneous purple scarring, which may be accompanied by arthralgia, abdominal pain, and renal lesions. Patients with knee pain can be treated with general therapy, oral medications, and systemic medications. 1. General treatment: most of this disease is self-limiting, requiring sufficient rest and reducing activities, which can relieve joint pain. 2. Oral medication: patients with allergic purpura knee pain can take non-steroidal anti-inflammatory drugs for treatment, such as ibuprofen, diclofenac sodium and other drugs, with antipyretic and analgesic effects. 3. Intravenous fluids: If necessary, patients can enter glucocorticoids such as hydrocortisone and dexamethasone intravenously for treatment, which can also improve the situation of allergic purpura knee pain. All of the above drugs should be used under the guidance of a doctor, and should not be used on their own, so as not to delay the condition. Patients with allergic purpura knee pain should go to the hospital in time and under the guidance of doctors for standardized treatment.