The common causes of foreign body sensation in kidney area are lumbar disc herniation, renal cyst, hydronephrosis and so on. 1. Lumbar disc herniation: lumbar disc is a cartilage structure between lumbar vertebrae, once the lumbar disc bulges or protrudes, this cartilage morphology change will compress the surrounding soft tissues, or compress the nerve root and spinal cord, if the compression degree is light, then there will be a foreign body sensation. 2. Renal cysts: they are common benign lesions of the urinary system. Most renal cysts are small in size and have no corresponding clinical symptoms; a small number of renal cysts are large in size and cause cystic compression symptoms, which are manifested as lumbar foreign body sensation, lumbar pain, lumbar pain, lumbar distension and other lumbar discomfort symptoms. 3. hydronephrosis: under normal circumstances, urine flows from the kidneys into the ureter, and then into the bladder, through the urethra to the outside of the body, urinary tract obstruction when the urine reflux or accumulation in the kidneys will lead to hydronephrosis, at this time the patient’s pressure in the kidneys, there will be a sense of discomfort. Renal colic and hematuria will also occur when there is more fluid accumulation, resulting in different degrees of renal function impairment. To sum up, it is recommended to go to the regular hospital in time to find out the cause of the foreign body sensation in the kidney area and follow the doctor’s instructions to standardize the treatment.