The causes of autoimmune diseases include changes in autoantigens, abnormalities in the immune system, genetic factors, and sex hormones. 1. Alteration of autoantigens: Infection, chemical substances, drugs, dampness, cold, local tissue injury, etc. can lead to the release of autoantigens, thus inducing autoimmune diseases. 2. Abnormalities in the immune system: influenced by environmental and genetic factors, the immune tolerance mechanism may be disturbed, thus causing autoimmune diseases. 3. Genetic factors: heredity is closely related to autoimmune diseases. 4. Sex hormones: Abnormalities in the levels of sex hormones and their metabolites are also causes of autoimmune diseases. There are many causes of autoimmune diseases, it is recommended that patients with autoimmune diseases go to the rheumatology and immunology department of regular hospitals and follow the doctor’s instructions for standardized treatment.