Does influenza cause fever?

Fever is the body's temperature response to infection. During influenza, immune signals can make you feel cold and shivery as your temperature rises; sweating may follow as it falls. You may also have headache, cough, sore throat, fatigue, or muscle aches. A thermometer can help you follow the trend, but the reading alone cannot establish that influenza is the cause.

Some people with influenza do not develop a noticeable fever, particularly older adults or people whose immune response is altered. Other infections can also cause fever, so the complete symptom pattern matters.

Rest and drink regularly to replace fluid lost through sweating or a reduced appetite. Wear light layers and keep the room comfortably cool rather than trying to chill yourself. If you use a fever or pain medicine, follow the package directions and ask a pharmacist about interactions or duplicate ingredients.

Do not give medicines containing aspirin to children or teenagers unless a clinician specifically advises it. Avoid strenuous exercise while feverish, and resume activity gradually once you are recovering.

Seek urgent help for breathing difficulty, chest pain, confusion, a seizure, collapse, or severe dehydration. Contact a clinician if fever is persistent or worsening, returns after you seemed better, or occurs with a serious long-term condition, pregnancy, reduced immunity, very young age, or older age. Infants with fever need age-specific medical guidance.

Ask which temperature readings or associated symptoms should prompt a call, whether you need testing, and which fever medicine is suitable for you. Share when the fever began, its pattern, your fluid intake, and any breathing or chest symptoms.