What temp is a fever?

In adults, a rectal or oral temperature of 100.4°F (38.0°C) or higher is the medical definition.

Fever: Causes & Ranges

Medical Emergency Notice

If you are experiencing severe symptoms like crushing chest pain, difficulty breathing, or loss of consciousness, please call 911 or your local emergency services immediately. This tool is for informational purposes only.

What is Fever?

Fever or pyrexia in humans is a symptom of an anti-infection defense mechanism that appears with body temperature exceeding the normal range caused by an increase in the body's temperature set point in the hypothalamus. There is no single agreed-upon upper limit for normal temperature: sources use values ranging between 37.2 and 38.3 °C in humans.

Fever is your body's defense mechanism against infection. A temperature of 100.4°F (38°C) or higher is generally considered a fever in adults.

What Are The Most Common Causes?

This symptom is frequently associated with the following conditions. Click on any condition to explore detailed symptoms, diagnosis, and treatment options.

Common Cold

Viral infection of the nose and throat.

Influenza

Sudden high fever with severe body aches.

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Is it Serious or Benign?

Most cases are temporary, but persistent or severe presentation warrants professional evaluation.

Associated Symptoms

May occur alongside fatigue, nausea, or localized discomfort depending on the cause.

General Home Measures

Safe steps some people use for temporary relief.

Drink plenty of fluids

Get adequate rest

Lukewarm sponge baths

What to Tell Your Doctor

Be prepared for your appointment.

Note the duration, severity, and any triggers for your symptom to help your healthcare provider make an accurate assessment.

When to Seek Urgent Care

Seek medical attention immediately if you experience any of the following "red flag" signs.

Fever over 103°F that doesn't respond to medication

Fever with severe headache or rash

Difficulty breathing

Frequently Asked Questions

Scientific References

This comprehensive symptom guide is based on established clinical guidelines and public health resources from authoritative sources.

Medically Reviewed for Accuracy

This content is aligned with established clinical guidelines and public health resources from authoritative medical institutions, including MedlinePlus, the CDC, and the NHS.

BodyWellness AI uses a structured clinical logic framework to present this information clearly and safely.