Flank pain refers to discomfort in your upper abdomen or back and sides. It develops in the area below the ribs and above the pelvis. Usually, the pain is worse on one side of your body.

Most people experience flank pain at least once in their life, and the discomfort is usually temporary. However, constant or severe flank pain may indicate a serious medical condition, such as dehydration or a urinary tract infection. Kidney stones or another kidney problem may also cause persistent flank pain.

Though flank pain is often a symptom of a kidney problem, it can also be the result of other medical conditions if it occurs along with additional symptoms. It’s important to see your doctor if you have chronic or severe flank pain, especially if you’re also experiencing other symptoms.

Some of the more common causes of flank pain include:

Less common causes of flank pain include:

Flank pain may be achy and dull or cramp-like and sharp. It may come and go in waves.

Symptoms of a kidney problem

The pain is likely due to a kidney problem if you also have the following symptoms:

You should call your doctor right away if you’re experiencing any of the above symptoms along with prolonged flank pain.

Symptoms of dehydration

You should also seek immediate medical care if you’re experiencing persistent pain along with these symptoms of dehydration:

It’s important to correct dehydration right away. When you lose too much water from the body, the organs, cells, and tissues fail to function as they should. This can lead to dangerous complications, including shock.

During your appointment, your doctor will try to identify the underlying cause of your flank pain. Be prepared to answer questions about:

  • the location of the pain
  • when the pain began
  • what the pain feels like
  • how often you experience the pain
  • how long you experience the pain
  • what other symptoms you have

Your doctor will also use blood tests and imaging tests to determine the cause of your flank pain. Imaging tests, such as ultrasounds or X-rays, allow your doctor to look deep within your body. They can reveal problems in the organs, tissues, and muscles.

Before performing these tests, your doctor may inject a contrast dye into one of your veins. They do this to improve the quality of the images. This makes it easier to identify any obstructions in your blood vessels or organs. The dye is usually iodine, and it rarely causes side effects.

Other diagnostic tests your doctor may recommend include:

  • an abdominal CT scan, which is a type of specialized X-ray that can show cross-sectional images of the abdomen
  • a cystoscopy, which is a minor procedure that involves inserting a thin tube with an attached camera into the bladder
  • a urinalysis, which is a simple urine test
  • a urine culture to detect bacteria in the urine

Rest is the primary treatment for any form of flank pain. Minor flank pain typically resolves with a combination of rest and physical therapy. Your doctor may also recommend specific exercises you can do for quick relief from muscle spasms.

Treatment for flank pain due to inflammation

For flank pain due to inflammation, such as can occur with infections and arthritis, the treatment will depend on the specific condition.

Kidney infections may require hospitalization. Your doctor will give you antibiotics if you have a kidney infection. They may give these antibiotics to you intravenously, or through a vein.

Physical therapy and exercise programs can often treat pain due to arthritis in the spine. Your doctor may also prescribe an anti-inflammatory medication, which will reduce the inflammation and discomfort. In some cases, people need surgery to correct a spinal problem.

Treatment for kidney stones

You’ll need to take pain medications and drink lots of fluids to encourage the passing of the kidney stone. In most cases, kidney stones don’t require surgery.

However, your doctor may perform a minor procedure called lithotripsy if larger kidney stones can’t easily exit your body during urination. Lithotripsy involves the use of high-frequency sound waves to break up the kidney stones so they can pass through the ureters.

The ureters are the tubes that carry urine from the kidney to the bladder. Your doctor may also use other surgical techniques to remove the stones.

Depending on your level of pain, your doctor may recommend over-the-counter or prescription pain relief medications. You may need to stay in the hospital. Talk to your doctor if you continue to experience intense or prolonged flank pain even after treatment.

You may be able to prevent flank pain by:

  • drinking at least eight glasses of water per day
  • limiting how much alcohol you drink
  • practicing safe sex and hygiene
  • eating a diet of mainly vegetables, fruits, and lean proteins

exercising at least three times per week