What should you know about adult fever range?

Temperature varies with time of day, activity and the measurement site. Use the same reliable digital thermometer and method when comparing readings, and record the result, time and any medicine taken.

A fever is part of the body's response to illness and commonly occurs with infections, but the reading does not reveal the cause. Respiratory symptoms may accompany a common cold, COVID-19 or acute bronchitis, while a painful spreading skin area can occur with cellulitis. Those conditions present in varied ways, so examination or testing may be needed.

Readings from the mouth, ear, forehead and armpit are not directly interchangeable. Technique, recent hot or cold drinks, exercise and a poor thermometer fit can distort the result. Feeling hot without measuring can be useful context but is less precise than a properly taken reading.

Rest, drink enough fluid to keep urine reasonably pale, wear light clothing and keep the room comfortable. Avoid ice baths and heavy wrapping. A pharmacist can check whether a fever-reducing medicine is suitable, particularly if you have liver or kidney disease, stomach ulcers, take other medicines or could be pregnant.

Recheck only often enough to follow how you feel and whether the temperature is settling. Note cough, rash, urinary symptoms, pain, travel, animal exposure and contact with illness; these details can help a clinician identify the source.

Get emergency help for severe breathing difficulty, blue or grey lips, confusion, collapse, a seizure, a stiff neck with severe headache, or a rash that does not fade when pressed. Severe chest pain and signs of shock also require immediate care.

Seek prompt advice for persistent fever, worsening symptoms, repeated vomiting, dehydration, painful urination, a spreading red and painful skin area, or significant immune suppression. A lower reading can still accompany serious illness in a frail adult, so urgency should follow the person's condition rather than the thermometer alone.

Tell the clinician how and where the temperature was measured, the pattern of readings, associated symptoms, recent travel or exposures, and all medicines taken. Ask whether testing is needed, how to maintain hydration and what specific change should trigger urgent reassessment.