In daily life, patients with lupus erythematosus may have relapses due to various infections, improper use of hormones, ultraviolet radiation, drugs, food and other reasons that can cause relapses. A relapse is considered if the following symptoms and abnormalities in laboratory tests occur: 1. More easily fatigued than usual, with no significant improvement after rest. 2. Unexplained fever or significantly increased blood sedimentation. That is, the fever cannot be explained by a cold, pharyngeal, pulmonary, or urinary tract infection, and is not due to other diseases. 3.Newly emerged vasculitis, fresh lesions appear, or accompanied by rash at the ends of fingers (or toes) or other parts, or the existing rash is aggravated; such as cheek erythema, discoid erythema, frostbite like lesions, polymorphic erythema like lesions, vasculitic skin lesions, perineal erythema, etc. 4. Swollen and painful joints appear; such as painful, red and swollen proximal interphalangeal joints, wrist joints, knee joints, ankle joints, etc., which may be accompanied by morning stiffness or joint effusion. 5.Hair loss is obvious. 6.Fresh ulcers of the mouth and nose. 7.The appearance of pleural fluid or pericardial effusion. 8.Newly appeared proteinuria or sudden increase in proteinuria, and red blood cells in urine routine. 9.Decreased white blood cells or platelets or significant anemia (routine blood tests for white blood cells, platelets and hematocrit are below normal levels. 10. The appearance of neurological symptoms, such as headache, vomiting, and convulsions. Theoretically, especially a decrease in C3 is one of the indications of disease activity, but the presence of simple decrease in complement and transient oral ulcers is not necessarily a sign of disease activity. The determination of whether SLE is relapsing should be based on a comprehensive analysis of symptoms and various test indicators, and should not be determined simply by certain laboratory indicators at a certain time.