1, why does allergic purpura damage the kidney and what are the chances of nephritis in patients? Because allergic purpura is a small vasculitis that affects the whole body, and the kidney has the most abundant capillaries, due to the recurrent attacks of purpura, it starts the immune mechanism and damages the kidney. In addition, the blood supply of kidney is in the way of artery in and artery out different from other organs. 2, How long will purpura nephritis appear after the appearance of allergic purpura? Nearly 90% of patients have an attack within a month, and most of them appear in 10-15 days. Of course it may also appear within six months, so follow-up review must be strengthened. 3.Does the medication for allergic purpura damage the kidney? Generally not, but we should pay attention to the damage of kidney by some immunosuppressants 4.What are the symptoms when kidney damage occurs? How much will the blood pressure rise and will there be hematuria in the naked eye? The earliest manifestation is the appearance of microproteinuria, followed by abnormalities in urine routine, mainly red blood cells on microscopic examination, with varying degrees of proteinuria, or even large amounts of proteinuria, edema, hypertension, and also sarcoid hematuria. The blood pressure can reach up to 200/130 or more. 5. Will purpura nephritis cause permanent kidney damage, will it lead to uremia, will it be life-threatening? If purpura nephritis is not treated in time, it can evolve into chronic damage, 1-3% can lead to uremia, and eventually can be life-threatening 6.Can purpura nephritis be completely cured? If the treatment is timely and the program is appropriate, it can be completely cured.