A temperature of 37.5°C or higher measured under the armpit, or 37.8°C or higher measured in the ear or rectum, is considered a high fever. Fever criteria are slightly different for infants and children. For infants in their first three months, measuring temperature under the armpit and rectally is accurate. If the temperature measured under the armpit is above 37.5°C, the infant should first be undressed. Infants are often overdressed in many layers of clothing out of concern that they will get cold, but this is incorrect. After slightly cooling the infant's environment, the temperature should be retaken after 15 minutes. If it remains above 37.5°C, a doctor should be consulted immediately.