Fever in Adults and Children: When to Worry and When to Visit the ER

Introduction
If you are otherwise healthy and alert, having a low-grade fever may not always be cause for alarm. Often, a mild fever means your immune system is working to fight off infection. However, an elevated temperature can sometimes signal another illness that requires treatment, and prolonged or severe fever can even cause complications on its own.

Because many different conditions can trigger similar symptoms, it can be difficult to self-diagnose. At iCare ER & Urgent Care in Frisco and Fort Worth, TX, our board-certified physicians provide prompt evaluation, testing, and treatment for adults and children with fever.

Learn more about what a fever is, what causes it, and when to seek medical attention at urgent care or the emergency room.

What Is a Fever?

For most adults, a normal body temperature is between 97°F and 99°F. A temperature of 100.4°F (38°C) or higher is generally considered a fever (CDC).

Common symptoms that may accompany a fever include:

• Sweating and chills

• Headache

• Body aches and fatigue

• Loss of appetite

Measuring fever accurately requires reliable tools. Types of thermometers include digital oral, ear, rectal, or forehead scanners (Mayo Clinic).

What Causes a Fever?

There are many possible causes of fever, ranging from minor to serious. Common causes include:

• Viral infections such as the flu or COVID-19

• Bacterial infections like pneumonia, strep throat, or urinary tract infections

• Heat exhaustion or dehydration

• Gastrointestinal illness, sometimes called a stomach bug

• Recent vaccinations (NIH)

A fever is often the body’s natural defense mechanism as the immune system raises temperature to help fight off infection.

How Long Does a Fever Last?

The duration of a fever depends on its cause, the patient’s overall health, and treatment.

• Viral fevers, such as influenza, often last 2 to 4 days

• Bacterial infections may persist until treated with antibiotics

• Prolonged fever can last several weeks in more serious conditions

If fever continues longer than 3 to 4 days in children, or if an adult fever does not improve with treatment, medical evaluation is needed.

How High Is Too High?

A temperature around 102°F may be uncomfortable but is usually manageable with fluids and rest. A fever of 103°F or higher is considered high grade and requires medical evaluation (Cleveland Clinic). Any fever in infants younger than 3 months requires immediate medical care.

In children and adults, persistent high fever can lead to dehydration, confusion, or seizures.

When to Seek Emergency Care for Fever

While many low-grade fevers can be managed at home with fluids and fever-reducing medications like acetaminophen or ibuprofen, you should go to the ER or call 911 if you experience:

• Fever of 103°F or higher

• Fever with chest pain, difficulty breathing, or confusion

• Severe abdominal pain, headache, or sensitivity to light

• Rash that spreads or worsens quickly

• Seizure or inability to stay awake

• Persistent vomiting or inability to keep fluids down

• Any fever in an infant under 3 months old

If you are unsure whether your fever is serious, it is safer to seek care promptly.

How Is Fever Treated in the ER?

At iCare ER & Urgent Care, evaluation for fever may include:

• Physical exam and medical history

• Vital signs measurement

• Laboratory tests such as blood tests or urinalysis

• Chest X-ray or imaging if infection is suspected

Treatment depends on the cause and may involve:

• Fluids to prevent dehydration

• Antibiotics for bacterial infections

• Antiviral medications in select cases

• Pain and fever relief with NSAIDs or acetaminophen

• Rest and monitoring

Conclusion

Most mild fevers can be treated at home, but certain situations require urgent or emergency care. A high fever in adults, prolonged fever in children, or fever with serious symptoms should never be ignored.

Visit iCare ER & Urgent Care in Frisco or Fort Worth for fast, professional evaluation and treatment. Our dual-hybrid model means you will receive the right level of care, whether urgent or emergency, all under one roof.

Learn more and find a location near you