Immune system disorders can be caused by exposure to allergens, infections, primary immune system developmental defects, abnormal lymphocyte proliferation, medications, and some immune system disorders for which no specific cause has been identified. Immune system disorders are a large group of diseases, including hypersensitivity disorders, autoimmune disorders, immunoproliferative disorders, immunodeficiency disorders, and other types of diseases. Their causes may be related to exposure to allergens, infections, primary immune system developmental defects, abnormal lymphocyte proliferation, and medications. Among them, hypersensitivity reactions include allergic rhinitis, hemolytic disease of the newborn, etc., and the pathogenesis is mainly due to the patient’s exposure to allergens, while the cause of immunoproliferative diseases is mainly due to the abnormal proliferation of lymphocytes. The exact cause of most autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, dermatomyositis, etc. is not yet clear, while immunodeficiency diseases are divided into primary and secondary, secondary immunodeficiency diseases are related to infections and malignant tumors, medications, etc., and primary immunodeficiency diseases are related to heredity. It is recommended that patients diagnosed with immune system diseases go to the rheumatology and immunology department of regular hospitals for consultation and targeted treatment under the guidance of doctors.