What are the characteristics of a fever? What are the different types of fever? When is a fever in an adult considered serious?

What are the Characteristics of a Fever?

A fever is a common side effect of illness like the flu. It happens when there is a temporary rise in body temperature. A fever is usually a sign that your immune system is busy fighting an infection or other illness. In babies and toddlers even a slight fever may be a sign of a serious illness, but in adults a fever is not usually serious or life-threatening.

A fever begins when your immune system makes more white blood cells to fight an infection. The increase in white blood cells triggers your brain to heat your body up. This causes a fever. In response, your body tries to cool itself off by tightening up on blood flow to your skin and contracting muscles, which makes you shiver and may cause muscle aches.

Your normal body temperature ranges from 97°F to 99°F (36.1°C to 37.2°C). You may have a fever if your temperature rises above this. Adults typically have a fever if their body temperature increases to 100.4°F (38°C). This is called a low grade fever. A high grade fever happens when your body temperature is 103°F (39.4°C) or above.

What are the Different Types of Fever?

Most fevers usually go away by themselves after 1 to 3 days. A persistent or recurrent fever may last or keep coming back for up to 14 days. A fever that lasts longer than normal may be serious even if it is only a slight fever, as a recurrent fever might be a sign of a more serious infection or health condition.

Common fever symptoms in adults include sweating, chills (shivering), headaches, muscle pain, loss of appetite, fatigue, and weakness.

When is a Fever in an Adult Considered Serious?

You should call your doctor immediately if you have a high grade fever — when your temperature is 103°F (39.4°C) or higher. Get medical help if you have any kind of fever for more than three days. Let your doctor know if your symptoms get worse or if you have any new symptoms.

A fever may be a sign of serious illness if you have a severe headache, dizziness, sensitivity to bright lights, stiff neck or neck pain, skin rash, difficulty breathing, frequent vomiting, dehydration, stomach pain, muscle cramps, confusion, or seizures. Other signs that a fever may be serious are pain when urinating, not urinating enough, passing dark urine, or passing urine that smells bad.

What Causes a Serious Fever in Adults?

Common causes of a serious fever in adults are viral infections (like the flu or a cold), bacterial infections, fungal infections, food poisoning, heat exhaustion, serious sunburn, inflammation (from conditions like rheumatoid arthritis), and tumors or blood clots.

Adults with certain chronic health conditions like asthma, rheumatoid arthritis, diabetes, Crohn’s disease, heart disease, or immune system disorders may be at higher risk of getting a serious fever. Certain medications and treatments can also lead to a serious fever, including antibiotics, blood pressure drugs, seizure medications, vaccines, steroids, chemotherapy, and radiation treatment.

How Can You Treat a Fever at Home?

A fever is not normally harmful on its own, and most fevers go away within a few hours to days as your body defeats an infection. You can help yourself feel better with at-home remedies like staying hydrated, eating light foods, using a cool compress, taking a warm sponge bath, and dressing in light, comfortable clothing.

Over-the-counter medications like ibuprofen, acetaminophen, or naproxen can also help ease your fever and symptoms like headaches and muscle pain. However, you may need treatment from your doctor for more serious causes of a fever, such as antibiotics, antivirals, or antifungals.

When Should You Seek Emergency Medical Attention for a Fever?

Get emergency medical attention by going to the ER or calling an ambulance if you have any of these symptoms along with a fever: seizure or convulsions, fainting or loss of consciousness, confusion, hallucinations, severe headache pain, stiff or painful neck, difficulty breathing, hives or a rash, or swelling in any part of the body.

A fever in adults is usually not serious, but a high fever or a fever that lasts more than three days can be a sign of a serious illness. Pay attention to any concerning symptoms and don’t hesitate to seek medical care if your fever is accompanied by serious or worsening symptoms.