The diagnosis of allergic purpura nephritis is mainly based on hemorrhagic rash and renal damage; typical rash helps to diagnose the disease, and those with sparse rash or those with renal symptoms when the rash has subsided should be followed up with detailed medical history (including joint and gastrointestinal symptoms) and rash pattern. The diagnosis is easier in the presence of typical renal symptoms, such as edema, hypertension, hematuria, proteinuria, nephrotic syndrome and renal insufficiency; for those with mild urinary changes, qualitative urinary protein (+) and urinary red blood cells over 5/high magnification are generally used as diagnostic criteria in China. Renal puncture biopsy is helpful for the diagnosis of this disease, and it helps to understand the extent of the lesion and assess the prognosis. Yang Meng, Department of Pediatrics, The First Affiliated Hospital of Henan College of Traditional Chinese Medicine