Low body temperature after a fever breaks

Sweating as a fever settles can cool the skin, and a tired person may feel chilled during recovery. Readings also vary with the thermometer, measurement site, room temperature, and recent drinks. A low reading may be more concerning when paired with unusual sleepiness, confusion, pale or cold skin, shivering that does not settle, breathing changes, or worsening infection symptoms. Fever can accompany illnesses such as a common cold, COVID-19, or other infections.

Recheck with a reliable thermometer using the same method, keep the person dry and comfortably warm with light layers, and offer fluids if they are awake and able to drink. Avoid very hot baths, heating pads, or alcohol. Note the temperature, time, symptoms, medicines, and recent fever for the clinician.

Contact a clinician promptly if the low reading persists, the fever returns, or the person is getting worse. Seek emergency help for confusion, difficulty waking, severe breathing trouble, blue or grey lips, collapse, seizure, or signs of shock. Infants, older adults, pregnant people, and people with weakened immunity may need earlier advice.

Ask whether the thermometer method is reliable, whether medicines could affect the reading, and whether symptoms fit an infection such as acute bronchitis, cellulitis, or another condition.