Should I Worry About Severe Side Pain and Blood in Urine After 3 Days of Antibiotics for a UTI?

Urinary tract infections (UTIs) are typically treated with antibiotics, and most people begin to feel better within 48 to 72 hours. However, when new symptoms appear—especially severe side pain and blood in the urine—during treatment, it becomes a cause for concern. These symptoms can indicate that the infection is not responding to the medication or that it has progressed into a more serious condition. Understanding what these signs mean and when to seek medical help is crucial for preventing complications and ensuring proper recovery.

Understanding Normal UTI Recovery Timeline
During the first few days of antibiotic treatment, improvement in symptoms such as burning, frequency, and urgency is expected. Pain should gradually decrease, and overall comfort should increase. While mild discomfort may linger, symptoms should not worsen. New or intensified symptoms, particularly blood in the urine or flank pain, are not typical and suggest the infection may be progressing. Monitoring your body during these first few days helps you detect problems early.

Why New Symptoms Are a Red Flag
When symptoms worsen after starting antibiotics, it often signals that the treatment is not working effectively. Blood in the urine (hematuria) and severe side or flank pain can indicate complications. These symptoms may point to the infection spreading from the bladder to the kidneys, leading to pyelonephritis—a more severe and potentially dangerous condition. New symptoms should never be dismissed as a normal part of healing because they often reflect an underlying issue that requires medical evaluation.

Possible Progression to a Kidney Infection
A kidney infection is more serious than a bladder infection and often presents with symptoms such as fever, chills, nausea, vomiting, and severe pain on one side of the back or flank. Blood in the urine can also occur. When antibiotics fail to control an infection early, bacteria can travel upward into the kidneys. Kidney infections require stronger or longer antibiotic treatments and sometimes hospitalization. Without proper care, they can lead to long-term kidney damage or dangerous bloodstream infections.

Antibiotic Resistance as a Common Cause
Antibiotic resistance happens when bacteria no longer respond to medication. If the prescribed antibiotic is ineffective against the specific bacteria causing the UTI, symptoms may persist or worsen. Blood in the urine or increasing pain despite treatment is a strong indicator that the bacteria are not being controlled. In these cases, a urine culture and sensitivity test are essential. This test identifies the exact bacteria involved and which antibiotics will work effectively, helping guide proper treatment.

Incorrect Antibiotic or Incomplete Diagnosis
Sometimes the antibiotic chosen is not the right one for the infection, especially if treatment began without a urine culture. Not all UTIs are caused by the same bacteria, and some bacteria naturally resist certain antibiotics. Additionally, symptoms may not be caused by a simple UTI at all but by another condition such as kidney stones, sexually transmitted infections, or bladder inflammation. When new symptoms arise, reevaluation is necessary to ensure an accurate diagnosis and appropriate treatment.

Kidney Stones and Their Connection to Symptoms
Kidney stones can cause severe side pain and blood in the urine, which can mimic or accompany a UTI. Stones can block the urinary tract, making infections more severe or harder to treat. If a stone is present, antibiotics alone may not resolve symptoms. Imaging tests like ultrasound or CT scan may be needed to determine if a stone is contributing to the problem. Failure to address stones can lead to repeated infections or serious complications.

Complicated UTIs and Underlying Conditions
Some individuals are more prone to complicated UTIs due to underlying health issues such as diabetes, weakened immune systems, anatomical differences, or pregnancy. These cases often require longer or more specialized treatments. A simple short course of antibiotics may not be effective. New symptoms during treatment should be taken very seriously in these situations, as complications can progress quickly. A healthcare provider may need to adjust treatment or conduct further testing based on your medical background.

Importance of Urgent Medical Evaluation
When severe side pain and blood in urine appear during treatment, immediate medical attention is necessary. These symptoms could indicate a kidney infection, treatment failure, or a completely different problem. Delaying evaluation can allow the infection to worsen, potentially leading to kidney damage or sepsis. A healthcare provider may order a urine culture, blood tests, or imaging to determine the cause. Prompt action ensures the right treatment is provided before complications arise.

What to Expect During Medical Assessment
During evaluation, the doctor will review your symptoms and may perform a urine test to check for persistent bacteria or other abnormalities. A urine culture can identify the specific organism and guide antibiotic selection. Blood tests may check for infection spreading beyond the urinary tract. Imaging such as ultrasound may be used to assess the kidneys and rule out stones or obstructions. These tests help determine whether you need a new antibiotic, additional medication, or further treatment such as IV antibiotics.

When Current Treatment Must Be Adjusted
If symptoms worsen or new symptoms arise, your current antibiotic may need to be changed. A healthcare provider will choose a stronger or more targeted medication based on test results. In some cases, treatment may be extended for a longer duration. If a kidney infection is suspected, oral antibiotics may not be enough, and intravenous treatment could be needed. Adjusting treatment promptly increases the chances of full recovery and reduces the risk of complications.

Red Flags That Require Emergency Care
Certain symptoms require immediate emergency attention, including high fever, severe flank pain, vomiting, dizziness, or inability to urinate. These signs can indicate a severe kidney infection or systemic infection. Blood in the urine combined with increasing pain is also a serious warning sign. Seeking care quickly can prevent the infection from spreading or causing long-term harm. Never wait to see if severe symptoms improve on their own.

Severe side pain and blood in the urine after three days of antibiotic treatment for a UTI are not normal and should be taken seriously. These signs may indicate treatment failure, antibiotic resistance, a progressing kidney infection, or another underlying issue such as kidney stones. Prompt medical evaluation is essential to determine the cause and adjust treatment. Acting quickly ensures effective recovery and helps prevent dangerous complications. UTIs typically improve with treatment, but worsening symptoms always warrant professional care.

UTI, commonly known as urinary tract infection, is a very common type of infection of the urinary system. It can affect any area of your urethra, ureters, bladder, or kidneys. Symptoms often include the desire to pee frequently, discomfort while urinating, and pain in the sides or lower back. Visit UrgentWay, urgent care for UTI, for effective UTI treatment by our board-certified providers at any of our locations. Our experienced health care providers will discuss your diagnosis, provide urgent care uti treatment, and counsel you on preventative care and healthy choices.