Purpura nephritis is allergic purpura nephritis, lupus nephritis is lupus nephritis, compared with the two need to be evaluated according to the patient’s condition and pathological grading, can not generalize which one is serious. Allergic purpura nephritis is a systemic small-vessel vasculitis, which is common in children. It is mainly characterized by the deposition of immune complex IgA, and most children have a better prognosis, which is a self-limiting disease. In patients with negative proteinuria, the condition will improve after active treatment. Some patients with proteinuria may eventually develop chronic kidney disease; the prognosis is poor for those who are older, with acute nephritic syndrome or nephrotic syndrome onset. Allergic purpura nephritis is given ACEI/ARB such as enalapril and valsartan for patients with proteinuria; some patients need immunosuppressive therapy such as prednisone and cyclophosphamide. Lupus nephritis is a common and serious complication of SLE, and the pathogenesis has not been clarified. There are two main sources of immune complex deposition: circulating immune complexes and in situ immune complexes. The renal pathology shows a typical “full-bloom” phenomenon with the deposition of various immunoglobulin and complement components. Treatment of lupus nephritis includes immunosuppressive therapy such as prednisone, cyclophosphamide, and merti-macrolide, and supportive therapy for the associated manifestations and complications. Lupus nephritis cannot be cured clinically. If the dosage is reduced or the medication is stopped, the recurrence rate is high and the disease will continue to worsen. Whether lupus nephritis or purpura fulminans, patients should actively seek medical treatment to improve the quality of life, and follow the doctor’s instructions for active treatment to avoid delays.