Is the presence of hematuria after allergic purpura purpura purpura nephritis? Purpura nephritis is a disease caused by the multiple damage factors produced by allergic purpura involving the kidneys. Professor Yang pointed out that purpura nephritis can be diagnosed if a child has allergic purpura and has kidney damage within 6 months. Some children may develop hematuria and proteinuria soon after the symptoms of allergic purpura such as rash, arthralgia and abdominal pain; or they may develop after 3~6 months, both of which are purpura nephritis. There are also some children who visit the clinic because of hematuria and/or proteinuria found in physical examination. Pursuing the medical history can reveal that the child had allergic purpura several months ago, which can also be considered as purpura nephritis. However, even if a child with allergic purpura does not have proteinuria or hematuria, the possibility of purpura nephritis cannot be completely ruled out. To avoid possible kidney damage, doctors recommend testing the child’s urine microalbumin, a test that is more sensitive than routine urine protein testing and more convenient than quantitative 24-hour urine protein testing. This test is more sensitive than the routine urine protein test and more convenient than the 24-hour urine protein quantification test. The clinical test is also often used to detect whether the kidney tubular-interstitial injury by the “urine renal function” indexes such as β2 microglobulin, urine retinol-binding protein and NAG enzyme, and the kidney ultrasound can also be used to detect the morphological changes of the kidney to determine whether the allergic purpura has caused kidney damage in children. Do I have to have a kidney puncture to confirm the diagnosis of purpura nephritis? Renal puncture (renal pathology examination) can determine the severity of purpura nephritis and is the most effective way to guide treatment as well as determine the prognosis of the disease. If your child has high urine protein (more than 50mg per kilogram of body weight in 24 hours), serious kidney function impairment, or the effect of medication has not been good, then, if there is no contraindication, it is recommended to let your child have a kidney puncture and obtain kidney tissue specimens for renal pathology examination. The kidney pathology examination is the “gold standard” for diagnosing and judging the severity of purpura nephritis. However, because kidney puncture is an invasive test, parents often have concerns, or because of economic problems, if the child’s symptoms are not very serious, it can not be done first, the doctor first according to the experience and general treatment plan. If the child has recently (e.g. within 1 to 2 months) had a kidney puncture at another hospital and the treatment plan developed after the puncture is still not effective, when transferring to another hospital, be sure to bring the kidney pathology report from the original hospital to the receiving doctor for reference so that the treatment plan can be adjusted without having to do another kidney puncture. However, if the child is in a period of rapid progression and aggravation of nephritis, with symptoms such as high blood pressure, large amount of proteinuria and rapid impairment of kidney function, which indicates that the condition has changed significantly compared to the original kidney puncture, parents should accept the doctor’s advice and consider having another kidney puncture to clarify whether the kidney damage has further deteriorated. If a child needs a kidney puncture, he or she can register for a bed on the day of the visit (usually a 1 to 3 day wait). After admission, the doctor will inform the parents in detail about the purpose and risks of the kidney puncture, and teach the child to breathe prone and hold his or her breath to ensure the success of the puncture. After the puncture is completed, the child needs to be kept in the hospital for 24 hours for observation to detect and manage any possible complications in a timely manner. Renal puncture can usually be performed on the second or third day after admission. Can purpura nephritis lead to uremia? Most children with purpura nephritis have a good prognosis and usually recover within 6 months to 2 years after the onset of the disease. The rest of the children are left with only minor urine test abnormalities and require long-term follow-up. Some children may develop hypertension and kidney function impairment during the acute phase of nephritis, but it is only temporary and the blood pressure and kidney function will return to normal after the condition improves. A few children have severe symptoms at the beginning of the disease, and renal puncture nephropathological examination shows that the glomerular crescent is more than 75%, indicating that the kidneys have been severely damaged, such children will soon develop acute renal failure and chronic uremia. If purpura nephritis has been cured, it will not affect the child’s growth and development and future marriage and children, and will not appear uremic syndrome. However, a small number of children can be prolonged and develop renal insufficiency and uremia (about 14% of pediatric uremia). According to long-term prognostic statistical studies, about 1% to 3% of children with purpura nephritis may progress to uremia, and about 20% to 35% develop chronic kidney disease. Risk factors for persistent renal damage are associated with symptoms of severe proteinuria and nephritic nephropathy. Predictors of severe kidney disease or uremia include the following: bloody stools; persistent rash; manifestations of nephritis plus nephrotic syndrome (50% of patients progress to uremia within 10 years); renal histopathology suggesting extensive glomerular crescent formation; those presenting with nephrotic syndrome, hypertension, and rapidly deteriorating renal function, with most of the periglomerular crescents seen in renal tissue.