The kidney damage caused by allergic purpura can not rely solely on the routine urine occult blood to determine the severity of the disease, usually the occult blood 1+ indicates that the extent of kidney involvement is not very heavy, but also combined with the urine routine whether there are red blood cells, red blood cell morphology or normal kidney function, serious cases need to kidney puncture to see the pathological typing to guide treatment. Patients with kidney damage can use prednisone, usually 20-30mg/d morning dose, serious patients can be injected intramuscularly Depo-Provera 1ml, once a month, according to the improvement of the condition, after 2 weeks with the dose can be gradually reduced, until the urinary routine back to normal. The method of drug reduction, in the case of the disease has been stable, every 1 week to reduce 5mg, about the total course of the disease for about 3 months, until the remission of the drug, while you can take other antihistamines and regulate capillary permeability and fragility of drugs.