Fevers in Children & Common Misconceptions

FAQ about fevers in children and understanding why they occur.

Fever is one of the most common clinical symptoms managed by pediatricians. It is a leading cause of urgent care and emergency room visits, and a frequent cause of parental concern. There are many misconceptions surrounding fever in children.

How is a fever defined?

A fever is defined as a body temperature higher than 100.4º F. For young children and infants, a rectal thermometer gives the most accurate measurement—often more accurate than ear or forehead thermometers. Digital thermometers, used in the mouth or under the armpit, are other ways to measure a temperature in older children.

Is a fever alone considered an illness?

Fever is not an illness by itself, but rather a symptom of an underlying infection or illness. It is a normal body mechanism that has beneficial effects in fighting infection. When your child has a fever, the body’s internal thermostat, the hypothalamus, raises the “set point” body temperature to 100.4º F or higher in order to combat the infection.

By the time the illness resolves, the hypothalamus resets the internal temperature to normal levels, typically around 98.6º F. Pediatricians will often take into account the duration of the fever and overall condition of the child, combined with other signs and symptoms to establish an underlying diagnosis. Parents should be reassured that fever indicates your child has a working immune system and is in combat mode, fighting the infection.

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What are the most common causes of fever in children?

The most common causes of fever in healthy children are viruses. These illnesses usually resolve with time and supportive care. Antibiotics are never indicated for viral infections. In general, fevers caused by viral illnesses will not last longer than four or five days. 

Immunizations can occasionally cause a low-grade fever up to 24 hours after the injection. For infants younger than 2 months old, a fever (higher than 100.4º F measured rectally) may indicate a more serious infection and warrants an immediate call to your pediatrician or a trip to the emergency department.

Should I give my child anti-fever medication?

Parents are frequently concerned with the need to maintain a “normal” temperature in their sick child. However, a fever is not known to endanger a generally healthy child. The main reason to give your child an anti-fever medication should be to improve the child’s overall comfort during the illness. An uncomfortable child may not be as interested in eating or drinking, leading to more serious problems such as dehydration. And most pediatricians would agree that a sleeping ill child who has a fever should not be woken in order to give anti-fever medications.

The two most common antipyretic (anti-fever) medications used to lower the body’s temperature and alleviate discomfort are ibuprofen (Motrin) and acetaminophen (Tylenol). There is no evidence that fever itself worsens the course of an illness or that it causes long-term neurologic complications. There is also a misconception that high fevers, if left untreated, are associated with seizures, brain damage, and death. Febrile seizures are caused by a rapid rise in temperature—anti-fever medications do not prevent seizures in a child with a fever.

What dosage of anti-fever medication should I give my child?

It is important for parents to understand that the dosages for acetaminophen or ibuprofen are based on the child’s weight. Parents should check with their pediatrician or refer to the back of the medication box to determine the appropriate dose for their child.

There is no major difference between acetaminophen and ibuprofen in lowering a child’s temperature. Ibuprofen is generally not recommended for children younger than 6 months of age. Both ibuprofen and acetaminophen can have serious side effects if a child is given more than the recommended dose. It cannot be stressed enough: Remember to keep all medications in the household in a locked cabinet out of reach of the child. Acetaminophen (Tylenol) is the single most common ingredient implicated in ER visits for medication overdoses in children.

With a greater understanding of fever, parents should feel more at ease when working with their pediatrician to provide quality care for their child during a febrile illness.

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