Which department to consult for purpura depends on the different causes of purpura. The common causes of purpura are allergic purpura, primary immune thrombocytopenia, hyperthyroidism, systemic lupus erythematosus and so on. 1.Allergic purpura, whose main manifestation is bleeding spots on the body, purpura can be bilateral and symmetrical, but also joint pain, abdominal pain and other symptoms. Henoch purpura is divided into four types, skin type, joint type, kidney type, gastrointestinal type. According to the different subtypes to choose the appropriate department for consultation, dermatology, orthopedics, nephrology, gastroenterology. 2. Primary immune thrombocytopenia, a bleeding disorder mainly characterized by significant reduction in platelets, mainly manifested by bleeding tendency of the skin and organs, it is recommended to consult the hematology department, and the medicines include prednisone, gammaglobulin, and so on. 3. Hyperthyroidism, due to hyperthyroidism will cause secondary thrombocytopenia, and then appear purpura, this should also be the main treatment of the primary disease, it is recommended to go to the endocrinology department, the drugs include methylthiouracil and so on. 4. Systemic lupus erythematosus is an immune system disease that can involve multiple organs, and when it involves the blood system, it may lead to purpura, for which it is recommended to treat the primary disease first, and it is recommended to go to rheumatology, and the medicines include prednisone, and so on. There may be other causes of purpura, so it is recommended that patients choose the appropriate department according to their specific conditions and seek treatment as soon as possible.