The cause of reactive arthritis is related to genetic markers (HLA-B27), infections, and other factors, and the main symptoms include weakness, fever, joint swelling, and joint pain. Reactive arthritis is arthritis that occurs after an infection in the intestines, pharynx, respiratory tract, genitourinary tract, etc. Infections with pathogens such as bacteria, mycoplasma, chlamydia, and viruses can cause reactive arthritis. In addition, reactive arthritis is closely related to HLA-B27. Symptoms of patients are mainly categorized into systemic symptoms and arthritis symptoms, skin and mucous membrane symptoms. Patients with reactive arthritis may have systemic symptoms such as fatigue, fever, weight loss, etc., and the systemic symptoms are more prominent and are not affected by antipyretic drugs. In addition, patients may also have arthritic symptoms such as joint pain, joint swelling, joint effusion, etc., as well as dermatomal and mucosal symptoms such as skin pimples and skin rashes, and patients may also have ophthalmic and genitourinary tract symptoms. It is recommended that patients diagnosed with reactive arthritis go to the Department of Rheumatology and Immunology of regular hospitals and follow the doctor’s instructions for treatment.