Thermometers can be used to measure a person’s temperature, but a fever can be suspected without a thermometer. This is because there are common symptoms associated with fever, such as body aches, chills, redness of the skin, sweating or dehydration.

How to check if you have a fever without a thermometer?

Knowing the symptoms associated with a fever is the best way to determine if you have a fever when you are not able to take your temperature.

For example, people with a fever often have:

Body aches, weakness, and headaches: These pains are often accompanied by viruses such as influenza or colds as a result of inflammation resulting from the body’s immune response to the virus.

Chills: Many people with a fever get chills or shivering, even with a high temperature. This is because the body is trying to raise the temperature to treat the cause of the fever. People who get chills from a fever will still feel hot to the touch and should wear light clothing.

Red cheeks: Many people with a fever experience red cheeks. This occurs when the body opens blood vessels, a process known as vasodilation, which increases blood flow to the skin and causes redness.

Sweating and dehydration: Many people with a fever experience sweating, which is the body’s attempt to regulate temperature and cool off, but it can be dangerous if you don’t drink enough water.

“As the temperature rises, we can lose a large amount of fluid through sweating,” says Professor Jordana Haber. And if you think you have a fever, look for signs of dehydration, including dry mouth, extreme thirst or confusion.

Change in the feeling of your temperature: If you already have these common symptoms of a fever, you can also take your temperature based on how you feel.

Fever can make people feel hot or cold, says David Cutler, president of the Family Physicians Medical Group in Santa Monica. You may feel flushed (with pink skin) or shivering, both of which indicate that your body is trying to lower your temperature.

When trying to diagnose a fever without a thermometer, people often touch their forehead. But that won’t work, because your whole body feels hot. However, having someone else touch your forehead can be an effective way to detect a fever without a thermometer, Haber says, especially if you have those other symptoms.

For this procedure to be most effective, someone would have to touch their forehead, and then your forehead, so they can better sense differences in temperature. Of course, this practice is not as effective as using a thermometer to get temperature readings.

“Diagnosing temperature by touch gives you a qualitative answer, not a quantitative answer,” Haber says.

When to seek medical attention for symptoms of a fever:

In general, it is important to monitor the symptoms and severity of a fever, rather than the specific temperature a person is experiencing.

Children often have a high fever but behave normally. In this case, Cutler says, they likely won’t need medical attention.

However, a person with severe symptoms, such as severe confusion or difficulty breathing, should seek medical attention even if they have a low fever.

People who have trouble breathing, a rash, or a fever higher than 38°C should contact their doctor.