The causes of long-term urinary occult blood in children mainly include the following: 1. Symptoms caused by children suffering from nephritis. Children suffering from chronic nephritis, such as purpura nephritis will appear long-term urinary occult blood. In this case, children can be treated with dipyridamole in a timely manner. If there is a large amount of proteinuria, glucocorticoids, such as prednisone, should be used. 2. Caused by children with Nutcracker syndrome. If a child has Nutcracker syndrome, it can cause long-term occult blood in the urine, and the child’s body is long and thin.