Kidney damage caused by allergic purpura is called allergic purpura nephritis. This disease is commonly seen in children. Once allergic purpura nephritis occurs, the typical clinical symptoms in patients include joint pain, recurrent rashes on both lower limbs, and abdominal pain. Of course, some patients may also experience gastrointestinal bleeding and the passing of black stools. The main clinical manifestations concerning the kidneys are hematuria and changes in urine color, which can be macroscopic or microscopic hematuria, increased urine foam, and proteinuria. Of course, some patients may also experience edema, especially noticeable swelling of the eyelids and facial area upon waking up in the morning, as well as increased blood pressure. In severe cases of allergic purpura nephritis, patients may also experience renal dysfunction and more.