Fever occurs when body temperature becomes elevated well beyond normal levels. A fever is not a disease itself, but rather, a symptom that indicates that the body is trying to fight off a bacterial or viral infection by heating up the system and making it inhospitable to germs. Though fever can be a positive sign of the body's healthy defense, it can also leave children feeling uncomfortable, cranky, and generally not well.
Normal body temperature varies across the day and is usually highest in the evening. According to the National Institutes of Health, in children younger than 6 months of age, the daily variation in body temperature is small. In children 6 months to 2 years old, the body temperature varies daily about 1 degree. Daily variations gradually increase to 2 degrees per day by age 6. Body temperature can be raised by physical activity, strong emotion, eating, heavy clothing, medications, high room temperature, and high humidity.
Caregivers can measure their children's temperature using a thermometer. Many different kinds of thermometers are available today, including traditional mercury thermometers, forehead strips, and electronic monitors that fit in the ear, or which are swiped across the forehead. Thermometer placement (e.g., at what part of the body measurement takes place) is important. Thermometers may be designed for oral, anal, ear, underarm, or forehead placement. Thermometer placements at sites nearer to the inside of the body (e.g., the anus) tend to offer a more accurate temperature reading, at least when using traditional thermometers. However, such placements are also more inconvenient. Thermometers should be used as directed on product packaging or as directed by a physician to obtain an accurate reading.
For children, a rectal temperature of 100.5°F/38°C or greater should always be considered a fever. Lower temperatures than 100.5°F/38°C might also be considered fevers as well, depending on the child (as normal body temperature varies across children). In other words, fever occurs when body temperature is significantly elevated above what is normal for a given child. If a child tends to have a normal temperature which is on the lower side of the population average (of 98.6°F/37°C), then a body temperature above that level, but below 100.5°F/38°C might qualify as fever for that child.
Many parents fear that children's fevers will cause brain damage. Brain damage from a fever generally will not typically occur unless the fever is over 107.6°F/42°C. Many parents also worry that untreated fevers will continue to rise and won't stop. Untreated fevers caused by infection will seldom go over 105°F/40.5°C unless the child is overdressed or trapped in a hot place. As children's high fevers are potentially dangerous, it is a good idea for parents to contact their pediatrician for advice and/or seek emergency care if their child's fever approaches such extremes and does not respond to conventional efforts to bring it back down (e.g., with appropriately dosed fever-reducing medication).
Parents should consult with their children's doctor before giving them over-the-counter fever reducers such as acetaminophen or ibuprofen. These medications can harm children when their dosage is not correctly adjusted for children's age and weight. Parents who do offer their children a fever reducing medication should carefully follow their doctor's dosing advise, or product dosing instructions as printed on the medication package. Unless specifically prescribed by a doctor, children should never take aspirin for a fever, as aspirin can contribute to a devastating neurological disease called Reye's Syndrome, which starts with nausea and lethargy and may lead to coma, respiratory failure, and death.
Parents may also offer children non-medication methods for lowering fever, such as lukewarm baths, sucking on ice chips or popsicles, or placing cool compresses on the forehead or other body parts.
Parents should consult their children's doctor if a child's fever rises suddenly, lasts longer than two days, or any time a child becomes lethargic or non-responsive.