Flank Pain: Causes, Warning Signs and Care

Flank pain is discomfort along the side of the back below the ribs and can need assessment when it is severe, sudden, or accompanied by urinary or systemic symptoms.

It may be felt on either side, remain in one spot, or travel toward the lower abdomen or groin. The sensation can be aching, sharp, cramping, or sore when you move. Note whether it started abruptly, follows activity, or changes when you pass urine; those details help narrow the cause.

Seek urgent medical care for intense or rapidly worsening pain, fever or chills, repeated vomiting, fainting, confusion, blood visible in urine, or difficulty passing urine. These features can accompany infection, obstruction, dehydration, or another problem that needs prompt examination. Pregnancy, a weakened immune system, or known kidney disease are additional reasons to contact a clinician promptly.

The causes below are listed alphabetically, not as a ranking. Kidney infection can cause flank tenderness alongside fever, chills, nausea, burning when passing urine, or a frequent urge to urinate. Kidney stones may produce waves of severe pain that can move toward the groin, sometimes with nausea or blood in the urine. A urinary tract infection may cause burning, urgency, cloudy urine, or lower abdominal discomfort; symptoms can extend beyond the bladder in some cases.

Muscle strain, a rib or spinal problem, shingles, and conditions affecting nearby abdominal or pelvic organs can also produce pain in this area. The pattern of pain, accompanying symptoms, examination findings, and tests help separate these possibilities.

A clinician will ask about the location and timing of pain, urinary changes, bowel symptoms, fever, recent injury, medicines, pregnancy possibility, and past kidney problems. Examination may include checking the abdomen, back, temperature, hydration, and tenderness over the kidney area. A urine sample can look for blood or signs of infection. Depending on the findings, blood tests or imaging may be used to check kidney function, identify a stone, or look for another source of pain.

Care is matched to the diagnosis and your overall condition. A kidney infection is commonly treated with prescribed antibiotics and advice about fluids, with closer care if you are very unwell or cannot keep fluids down. Kidney stone care may include pain relief, anti-sickness treatment, hydration guidance, and assessment for a stone that is obstructing urine flow. A urinary tract infection may need testing and prescribed treatment. Pain from a strain may improve with relative rest, gentle movement, and suitable pain relief after checking what is safe for you.

Drink regularly enough to avoid frequent dehydration, especially in hot weather, during exercise, or when ill. Do not delay passing urine when you need to go. If you have had a kidney stone or recurrent urinary infections, follow the prevention plan tailored by your clinician, because the advice can differ with the underlying cause. Use safe lifting technique and build activity gradually to reduce avoidable back and side strain.

Mention burning or urgency when passing urine, a change in urine colour or smell, fever, nausea, vomiting, pain moving to the groin, rash, bowel changes, vaginal bleeding or discharge, and any recent fall or heavy lifting. Bringing a list of regular medicines and noting whether the pain is linked to meals, movement, or urination can make the consultation more useful.

Some people can start treatment and monitor symptoms at home, while others need same-day testing, imaging, or hospital care. Follow the plan you are given and seek reassessment if pain worsens, a fever develops, you cannot drink, or urinary symptoms change. A follow-up may be used to confirm that infection has settled, symptoms are improving, or a stone has passed or been managed.