Flank pain what it can mean
Informed by recognized medical guidance
Overview
Flank pain is pain or discomfort on one side of your body, between your lower ribs and your hip. It often comes from problems with the kidneys or urinary system, but can also be caused by muscles or bones in that area.
Key facts
- Flank pain can be sharp, dull, constant, or come and go.
- The most common causes are kidney stones and urinary tract infections.
- Most flank pain is not an emergency, but some causes need quick medical attention.
Yes, flank pain is quite common. Many people experience it at some point, often due to kidney stones, a urinary tract infection, or a muscle strain.
Flank pain can affect people of all ages, but it happens more often in adults, especially those between 30 and 60 years old. People with a history of kidney stones, urinary infections, or dehydration are at higher risk.
Symptoms
- Sudden, severe flank pain that makes it hard to sit still or find a comfortable position
- Flank pain along with a high fever (over 101°F or 38.5°C) and chills or shaking
- Pain that comes with nausea and vomiting and you cannot keep fluids down
- Not being able to pee at all, or passing very little urine
- Blood in the urine (visible) along with severe pain
- ⚠Flank pain that lasts more than a day or gets worse
- ⚠Pain that is not relieved by over-the-counter pain relief (like paracetamol or ibuprofen – but do not take without checking with a pharmacist or doctor)
- ⚠Pain together with a burning feeling when you urinate
- ⚠Flank pain in someone with a known kidney condition (such as chronic kidney disease)
Common symptoms
- Dull ache or sharp, stabbing pain on one side of the back or side
- Pain that comes in waves or gets worse with movement
- Pain that travels to the lower belly or groin area
- Pain when urinating or needing to urinate often
- Cloudy, dark, or bloody urine
- Fever or chills (if infection is present)
Symptoms in children
- Fussiness or crying more than usual
- Pain that makes them bend over or hold their side
- Wetting the bed or having accidents if they are already toilet trained
- Fever without a clear cause
Symptoms in older adults
- Pain that is less sharp but more constant, or confusion due to infection
- Changes in urination, such as leaking or not being able to empty the bladder
- Fever or low body temperature
- Loss of appetite or feeling generally unwell
Causes
Main causes
- Kidney stones – hard deposits that form in the kidney and can block the urinary tract
- Urinary tract infection (UTI) or kidney infection (pyelonephritis)
- Muscle strain or injury to the back or side
- Shingles – a painful rash that can affect one side of the body
- Other less common causes: kidney cysts, tumors, or swelling of the kidney (hydronephrosis)
Risk factors
- Not drinking enough water (dehydration)
- A diet high in salt or animal protein
- Family history of kidney stones
- Being overweight or obese
- Having a weakened immune system (for infections)
- Recent injury to the back or side
When to see a doctor
See a doctor urgently if:
- Severe pain that comes on suddenly and makes you unable to function
- Pain with fever, chills, or shaking
- Blood in your urine that is clearly visible
- You cannot urinate or have very little urine
Book a routine appointment if:
- Mild to moderate flank pain that lasts more than a day or two
- Pain that keeps coming back
- Unusual changes in how often you urinate or the color of your urine
Diagnosis
Your doctor will ask about your pain, your medical history, and do a physical exam. They will check your back and belly and may press gently on the area to see where it hurts.
Tests that may be done
- Urine test (urinalysis) to look for infection, blood, or crystals
- Blood tests to check kidney function and signs of infection
- Imaging tests such as an ultrasound, CT scan, or X-ray to see the kidneys, ureters, and bladder
What to expect at your appointment
Most tests are painless and done in a clinic or hospital. You might need to give a urine sample and have blood drawn. If an infection is found, treatment often starts quickly. For kidney stones, you may be referred to a specialist.
Treatment
Treatment depends on the cause of the flank pain. For most causes, the goal is to relieve symptoms, treat any infection, and prevent future problems. Many causes can be managed at home with simple measures.
Self-care at home
- Rest the area – avoid heavy lifting or twisting movements
- Apply a heating pad or warm compress to the painful area for 15-20 minutes at a time
- Drink plenty of water – aim for 6-8 glasses a day unless your doctor advises otherwise
- Take over-the-counter pain relievers such as paracetamol or ibuprofen (check with your pharmacist that they are safe for you)
Medical treatments
If a bacterial infection is causing the pain, your doctor will prescribe antibiotics to clear the infection. For kidney stones, pain may be managed with stronger medication, and sometimes a procedure is needed to break up or remove the stone. For muscle strains, physical therapy or muscle relaxants may be recommended. Do not take any medication without first consulting your healthcare provider.
When is surgery considered?
Surgery may be needed for large kidney stones that do not pass on their own, for tumors, or for severe blockages in the urinary tract. Your doctor will discuss the options and risks with you.
Living with this condition
Most people with flank pain recover fully once the cause is treated. If you have a chronic condition like repeated kidney stones, you may need to make long-term changes to prevent recurrence.
Lifestyle tips
- Stay well hydrated by drinking water throughout the day
- Limit foods high in salt, such as processed snacks and canned soups
- Maintain a healthy weight through balanced eating and regular physical activity
- Avoid holding your urine for long periods – empty your bladder when you feel the urge
Diet and exercise
A diet low in salt and animal protein may help prevent kidney stones. Include plenty of fruits and vegetables. Gentle exercise like walking is fine once you feel better, but avoid heavy lifting until your doctor says it is safe.
Mental health and emotional wellbeing
Dealing with repeated pain or a chronic condition can be stressful and frustrating. It is normal to feel worried or down. Talk to your healthcare provider if pain or health worries are affecting your mood or daily life.
Prevention
Many causes of flank pain can be prevented by staying hydrated, eating a balanced diet, and practicing good hygiene to avoid urinary tract infections. There is no guaranteed way to prevent all cases.
Vaccines
Vaccinations for shingles (if you are over 50) can reduce the risk of getting shingles, which can cause flank pain. Ask your healthcare provider if you are eligible.
Screening programmes
Routine screening for kidney stones or other causes of flank pain is not recommended for most people. If you have a family history or recurrent problems, your doctor may suggest periodic check-ups.
Complications
If left untreated
- Kidney infection can spread to the bloodstream and become life-threatening (sepsis)
- Large kidney stones can block the flow of urine and damage the kidney
- Chronic kidney disease if the underlying cause is not addressed
Long-term outlook
The outlook for flank pain is generally very good. Most causes are treatable, and with proper care, people recover fully. If you have a chronic condition like kidney stones, you can manage it with lifestyle changes and follow-up care. Seek medical help early to avoid serious problems.
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Always verify with your doctor
Health guidelines vary by country and region. The information in this article is based on international clinical guidelines but may not reflect the specific guidelines, medications, or practices in your country. Always discuss your health concerns with your own doctor or healthcare provider, and refer to your local national health guidelines where available.
Important notice This information is for educational purposes only. It does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your specific situation. If you are experiencing a medical emergency, call your local emergency services immediately.
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Sources and guidance
This article is educational and is prepared with reference to recognized health information and clinical guidance sources where available. Specific source links may vary by topic.
Last updated: July 16, 2026
Educational note: This information is for education only and is not a diagnosis.
Use it to support, not replace, advice from a licensed clinician.
If symptoms are severe, worsening, or urgent, call your local emergency number or seek emergency care.
Guidance may differ by country or region. Confirm local recommendations with a qualified healthcare provider.