- Fever, chills, vomiting, or back, side, or groin pain may be signs that a UTI has spread to the kidneys and needs urgent medical care.
- Blood in the urine or pain and burning with urination should not be ignored, especially if symptoms get worse quickly.
- In babies and older adults, warning signs may be less obvious and can include unexplained fever, irritability, poor appetite, or confusion.
UTI symptoms often include burning when urinating, frequent urination, and dark or strong-smelling urine. Other signs like fever, chills, lower back pain, or blood in the urine may appear depending on how severe the infection is.
UTI symptoms can vary based on the part of the urinary tract affected, such as the urethra, bladder, or kidneys. More serious infections, like kidney infections, may cause high fever, nausea, and intense pain in the back or abdomen.
Most UTI symptoms are caused by bacteria entering the urinary tract, with Escherichia coli being the most common. UTIs are more frequent in women, but they can also affect men, babies, and pregnant women, sometimes with different or less obvious symptoms.
What are the symptoms of a UTI?
The most common symptoms of a UTI include:
- Pain or burning with urination (dysuria)
- Bladder heaviness or pelvic pressure
- Urinary frequency
- Urinating small amounts at a time
- Very dark and foul-smelling urine
- Low-grade fever
- Chills
- Lower back pain (in more severe cases)
- Blood in the urine (in some cases)
If signs or symptoms of a UTI are present, a healthcare provider should evaluate them to confirm the infection and determine whether antibiotic treatment is needed, according to the CDC.
Online symptom checker
If you think that you may have a UTI, report your symptoms below:
This symptom checker is only a tool and is not meant to diagnose any condition or replace an appointment with a healthcare provider.
UTI symptoms by infection type
A UTI can cause different symptoms depending on where the infection is located in the urinary tract. Common types of UTIs include:
1. Urethritis: infection in the urethra
Urethritis happens when the bacteria causing the UTI affects only the urethra. This can lead to inflammation and symptoms such as:
- Frequent urination
- Difficulty urinating
- Pain or burning when urinating
- Yellow discharge from the urethra
Treatment usually involves antibiotics to eliminate the bacteria causing the infection. Keeping the area clean and dry and increasing daily water intake can also help support recovery.
2. Cystitis: bladder infection
A bladder infection is a common type of UTI. It happens when bacteria travel through the urethra and reach the bladder, which can cause symptoms such as:
- Urgent need to urinate, even if only small amounts come out
- Burning or pain when urinating
- Blood in the urine
- Cloudy, strong-smelling urine
- Pain or pressure in the lower abdomen
- Low-grade fever (in some cases)
It’s important to see a healthcare provider as soon as any of these symptoms appear so that antibiotic treatment can begin promptly and prevent the infection from spreading to the kidneys.
Back pain, a fever of 38 ºC (100.4 ºF) or higher, or vomiting may mean the infection is getting more serious and needs to be checked right away in the emergency room.
3. Pyelonephritis: kidney infection
Most UTIs involve only the urethra or bladder. However, in more severe cases, bacteria can travel up to the kidneys and cause a serious infection known as pyelonephritis. This condition can lead to symptoms like:
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Fever above 38.5°C (101.3°F)
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Severe pain in the abdomen, back, or groin
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Pain or burning sensation during urination
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Presence of pus or blood in the urine
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Frequent urge to urinate
Other possible symptoms include chills, nausea, vomiting, fatigue, and, in older adults, confusion as an early sign.
According to the National Institute of Diabetes and Digestive and Kidney Diseases, kidney infections can also cause fever, painful or frequent urination, and pain in the back, side, or groin, and they require prompt medical care.
If pyelonephritis is suspected, treatment should be started right away in the hospital and usually includes intravenous (IV) antibiotics.
UTI symptoms in babies
Detecting a urinary tract infection (UTI) in babies can be challenging, since infants and young children cannot describe how they feel. However, some common signs to look out for include:
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Fever above 37.5°C (99.5°F) without an obvious cause
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Crying or discomfort during urination
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Urine with a strong or unusual smell
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Blood in the diaper
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Persistent irritability
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Poor appetite
If you notice any of these symptoms, have your baby evaluated by a pediatrician as soon as possible.
UTI symptoms during pregnancy
Symptoms of a UTI while pregnant are generally the same as those that occur when you are not pregnant. However, some pregnant people may only learn they have an infection during a routine urine test, as they might not experience any noticeable symptoms.
UTIs are more common in pregnancy because the immune system is naturally less active, and higher levels of protein in the urine can encourage bacterial growth.
Commonly used antibiotics such as cephalexin (Keflex) and nitrofurantoin (Macrobid) are considered safe and effective for treating UTIs during pregnancy.
Confirming a diagnosis
The diagnosis of a UTI is confirmed with urine tests. A urine culture identifies the specific bacteria causing the infection and helps determine the most effective antibiotic.
In some cases, particularly when pyelonephritis is suspected, imaging tests such as an ultrasound or MRI may also be ordered.
What causes UTIs?
Urinary tract infections (UTIs) occur when bacteria enter the urinary system. The most common cause is Escherichia coli (responsible for about 70% of cases).
Other bacteria that can cause UTIs include Staphylococcus saprophyticus, Proteus and Klebsiella species, and Enterococcus faecalis.
How to prevent a UTI
You can help prevent a UTI by following these recommendations:
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Wash the external genital area with mild soap and water after sexual intercourse.
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Clean from front to back after urinating or having a bowel movement to prevent E. coli bacteria from reaching the urethra.
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Empty your bladder completely each time you urinate to reduce the amount of residual urine, which can promote bacterial growth.
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Drink plenty of fluids, ideally at least 1.5 liters (around 6 full 8‑oz glasses)of water or other clear liquids per day.
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Eat a high-fiber diet to promote regular bowel movements and reduce the time bacteria stay in the intestines.
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Avoid scented products such as perfumes, sprays, or creams in the genital area, as they can irritate the skin and increase infection risk.
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Wear loose-fitting clothing and avoid daily pantyliners to prevent excessive moisture and heat buildup in the area.
These preventive measures are especially important during pregnancy, when hormonal changes and increased pressure on the bladder raise the risk of developing a UTI.