Understanding Fever in Adults: When to Worry

A fever is a common sign that your body is fighting an infection. While often uncomfortable, it’s a natural and generally beneficial response. This article will explore what constitutes a fever, its causes, and when it’s important to seek medical attention.

What is a Fever?

The average normal body temperature is around 98.6°F (37°C), but this can vary throughout the day and from person to person. A fever is generally defined as a body temperature of 100.4°F (38°C) or higher Harvard Health. However, it’s important to consider your baseline temperature, as what’s considered a fever for one person may not be for another. Normal body temperature can fluctuate, rising after eating or exercise Harvard Health.

Levels of Fever Severity

Fevers are categorized based on their severity:

• Low-grade: 99.1 to 100.4°F (37.3 to 38.0°C)
• Moderate-grade: 100.6 to 102.2°F (38.1 to 39.0°C)
• High-grade: 102.4 to 105.8°F (39.1 to 41°C) Harvard Health

The body’s temperature often fluctuates throughout the day, being higher in the afternoon than in the morning Harvard Health.

What Causes a Fever?

Fevers are most often caused by infections, whether viral (like the flu or COVID-19) or bacterial (like strep throat) OSF HealthCare. When your body detects these invaders, it raises its temperature to create a less hospitable environment for them. A higher temperature helps the immune system work more effectively Harvard Health. Fevers can as well be triggered by allergic reactions to food or medication OSF HealthCare.

When to Seek Medical Attention

While many fevers can be managed at home, certain situations warrant a visit to the doctor. You should seek medical aid immediately if you experience a fever over 104°F (40°C) Harvard Health, or if your fever is accompanied by any of the following symptoms:

• Seizure
• Loss of consciousness
• Confusion
• Stiff neck
• Trouble breathing
• Severe pain
• Swelling or inflammation
• Vaginal discharge that is discolored or smells bad
• Pain when urinating or urine that smells bad Harvard Health

A low-grade fever between 100.4 and 102.2°F (37.3 to 39.0°C) is usually considered a low-grade fever and may not require medication OSF HealthCare.

Key Takeaways

• A fever is a natural response to infection.
• Normal body temperature varies, but a fever is generally considered 100.4°F (38°C) or higher.
• Most fevers can be managed at home, but seek medical attention for high fevers or concerning symptoms.