Left Flank Pain and Fever: What to Know

The flank is the area between the ribs and hip on your back or side. Fever alongside pain can occur when the body is responding to infection. A kidney infection commonly presents with flank pain and fever, and may also cause chills, nausea, burning urination, or a frequent urge to pass urine. A kidney stone can cause severe, wave-like pain and may block urine flow; infection behind a blockage needs urgent attention. A urinary tract infection can sometimes spread upward toward a kidney. Muscle strain usually does not cause a fever, so the combination deserves more than simple home treatment.

Arrange same-day medical advice if you have flank pain and a measured fever, even if urinary symptoms are mild. Sip fluids if you can keep them down, rest, and note when the pain and fever began. Do not use leftover antibiotics, because the right treatment depends on the cause. A clinician may ask about urination, examine your abdomen and back, and arrange urine or blood tests; imaging may be considered when a stone or blockage is suspected.

Go to urgent care now for confusion, fainting, severe or rapidly worsening pain, repeated vomiting, inability to pass urine, shaking chills, or trouble breathing. Seek prompt help if you are pregnant, have one working kidney, or have a weakened immune system. These features can indicate a serious infection, dehydration, or obstruction that should not wait.

Could this be a kidney infection, stone, or another cause? Do I need a urine test or imaging? Which pain or fever medicines are suitable for me? What changes should make me return urgently?