11 Symptoms To Watch Out for if You Get an E. Coli Infection (2024)

Escherichia coli, or E. coli, are usually harmless bacteria commonly found in your intestines. However, some strains of E. coli produce a substance called Shiga toxin, which causes infections. If you develop an E. coli infection, you'll likely experience symptoms such as nausea, abdominal cramps, and diarrhea. These symptoms usually occur between one and 10 days of exposure to the bacteria. Symptoms usually resolve within five to 10 days, but may last up to two weeks.

You might develop an E. coli infection after eating contaminated food or swallowing contaminated water. Everyone experiences the infection a little differently. In some cases, symptoms may worsen and the infection can cause complications. Up to 10% of E. coli infections progress to hemolytic uremic syndrome (HUS), which can lead to kidney failure and become fatal. That's why it's important to learn the signs and understand when it's time to seek medical care.

E. coli infections most commonly affect the gastrointestinal (GI) tract, which is a passageway in your digestive system that connects your mouth to your anus. As your immune system works to fight off the infection, your GI tract can become inflamed and cause the following symptoms:

• Diarrhea: One of the hallmark symptoms of E. coli is watery stools (poops) that can be uncomfortable to pass. In some types of E. coli infections, you might notice that your diarrhea is bloody. This can cause your stools to become bright red, dark red, or black in color.
• Abdominal pain: Stomach cramping and abdominal pain can also accompany E. coli infections. The pain may feel sharp, severe, and persistent.
• Nausea and vomiting: E. coli infections often make you feel nauseous. Vomiting and diarrhea also increase your risk of dehydration, so it's especially important to drink lots of water as you recover.

Keep in mind: the severity of symptoms varies from person to person. Some people don’t have any symptoms at all, while infants and older adults may be more vulnerable to experiencing complications.

Systemic Symptoms

While most E. coli infections affect your GI tract, sometimes these infections can cause systemic symptoms—meaning that you can develop symptoms that affect your whole body. These symptoms include:

• Fatigue: As your body fights off the infection, it's very common to feel tired and fatigued. The additional symptoms of diarrhea, stomach pain, and vomiting can also worsen your exhaustion. Because your immune system is taking extra energy to help you heal, rest is a key to recovery.
• Fever: Having a fever can sometimes accompany an E. coli infection. In most cases, the fever will be mild to moderate and should be lower than 101 degrees Fahrenheit. If the fever climbs above 102 degrees Fahrenheit, contact your healthcare provider.

In some cases, E. coli infections can also cause bacteria to enter your urinary tract and increase your risk for urinary tract infections (UTIs). People assigned female at birth are more likely to develop UTI symptoms alongside other symptoms of E. coli. In addition to GI symptoms, you may also experience the following:

• Pain while urinating: Discomfort in your stomach or urethra as you pee
• Needing to urinate more often: Using the restroom multiple times an hour
• Having a sudden urge to pee: Needing to go to the bathroom even if you just went
• Feeling unable to empty your bladder: You may feel like your bladder isn't completely empty, which can cause you to have the urge to pee several times throughout the day
• Abdominal pain and back aches: Pain during urination can cause discomfort in your stomach and back
• Changes in urine: Your pee may look cloudy, be foul-smelling, or appear bloody

Complications

In certain cases, E. coli infections can cause hemolytic uremic syndrome (HUS)—a serious complication that affects your kidneys. HUS is most often seen in children younger than five years of age, but adults who are immunocompromised may also experience this potentially fatal (deadly) condition.

The symptoms of HUS tend to develop about a week after you start having diarrhea and abdominal pain. HUS may also cause the following symptoms:

• Extreme fatigue
• Fainting
• Loss of pink pigmentation (color) in your cheeks or eyelids
• Jaundice, a yellowing of the skin
• Shortness of breath
• Decreased urination
• Blood in the urine
• Seizures, in rare cases
• Kidney failure, if the condition is left untreated

If you or your child are experiencing HUS symptoms, it's important to see a healthcare provider as soon as possible. Getting treatment for the condition early can decrease the risk of worsening symptoms and death.

Generally, E. coli is more prevalent—and dangerous—in those with weaker immune systems, including infants and children. In particular, children under the age of five are most at risk for developing severe symptoms.

Typical signs of an E. coli infection in children include:

• Bloody diarrhea
• Vomiting or an inability to keep food or liquids down
• Stomach aches
• Reduced urination
• Dehydration
• Headache

If a child's infection progresses to HUS, they may experience these additional symptoms:

• Extreme fatigue
• Crankiness or irritability
• Pale skin
• Fainting
• Muscle weakness
• Swelling in the legs, ankles, and feet

When to Contact a Healthcare Provider

In most cases, symptoms of E. coli infections clear up on their own within five to 10 days of onset, even without medical attention. However, more severe cases require care from a healthcare provider. Contact your provider or seek emergency care if you or your loved one experience any of the following:

• Diarrhea lasting more than three days
• A fever of 102 degrees Fahrenheit or higher
• Blood in urine or poop
• Excessive vomiting
• Infrequent urination
• Extremely pale skin

E. coli bacteria are often harmless, but some types can cause infections that mostly affect your gastrointestinal tract. As a result, you'll likely experience symptoms like diarrhea, abdominal pain, and nausea. It's also common to feel fatigued or develop a fever as your body tries to recover from the infection.

In rare cases—and especially among vulnerable populations like children under the age of five or adults over the age of 65—an E. coli infection can cause complications. The most common complication is called hemolytic uremic syndrome (HUS), which can cause severe symptoms and even kidney failure if the condition is left untreated. If your symptoms aren't going away within a week or are getting worse, see a healthcare provider to learn about your treatment options.