Causes of Flank Pain

Flank pain is pain that is located on the sides, below the ribs and between the abdomen and back, and usually occurs on just one side of the body at a time. People with flank pain that persists after rest, is severe or is accompanied by other symptoms should be evaluated by a doctor, who may order tests such as urinalysis, ultrasound or computerized tomography (CT) scans to make a diagnosis. Consider this information derived from the Mayo Clinic and the National Library of Medicine about the causes of flank pain.

Bone and Muscular Disorders

• People with arthritis of the spine may experience pain in the lower back and flank, which may cause difficulty with exercise and other physical activity. Degenerative disk disease or a slipped or herniated disk in the lower back may cause people to experience pain in the back and flank. People with a pulled or strained muscle or who have muscle spasms may also experience flank pain.

Circulatory Disorders

• Disorders of the circulatory system may cause people to develop flank pain. People who have blood clots in the artery that services the kidney, which is a condition referred to as renal artery thrombosis, may develop flank pain, swelling and inflammation of the area. People with hardening or plaque buildup in the renal artery may also experience flank pain.

Kidney Disorders

• People with certain disorders of the kidney may experience flank pain. Kidney cancer, polycystic kidney disease and kidney stones may cause flank pain, which may be intense. People with bleeding in the kidneys or pyelonephritis (kidney infection) may also experience flank pain, as well as fever, skin changes, fatigue and urinary problems.

Shingles

• People with shingles infections may develop pain in the flank that is accompanied by a rash in the same area. Shingles may cause extreme sensitivity and pain in the area of the rash, and even the pressure of clothing may be unbearable. Flank pain caused by shingles infections may last for several weeks or longer, and may be reduced with over-the-counter or prescription-strength pain relievers.

Urinary Tract Infection

• People with urinary tract infections (UTIs) may experience flank pain, and these infections can occur in people of any age. UTIs are more common in women than men, and pain may only develop once the infection has spread into the bladder or kidneys. Flank pain caused by UTIs may be accompanied by fever and painful or difficult urination.