What should you know about dangerous body temperature?

A fever is a body response to infection or inflammation. The reading can vary with the measurement site, device, recent activity, clothing, and age. The number matters, but the person’s overall condition matters too. Acute Bronchitis, Bronchiolitis, Brucellosis, Cellulitis, Chickenpox, Common Cold, COVID-19, and Croup are examples of conditions that may be associated with fever, each with different features and treatment needs.

A single reading cannot identify the cause. Record the value, time, method, and associated symptoms so a clinician can judge the pattern.

Rest and offer frequent fluids when appropriate. Keep clothing light and the room comfortable. Recheck using the same reliable method rather than repeatedly switching devices. Use fever medicine only as directed for the person’s age, weight, health conditions, and other medicines; never combine products without checking their ingredients. Do not use cold-water immersion or alcohol rubs.

Get urgent medical help for confusion, difficulty breathing, a stiff neck, a seizure, severe headache, severe pain, a widespread concerning rash, fainting, blue or grey lips, inability to drink, or very little urine. Seek prompt advice for a baby with fever, a person with a weakened immune system, or fever that is worsening or not settling.

Ask which thermometer method is most suitable, how often to recheck, which medicine and dose fit the person, and what changes should trigger same-day or emergency care.