Fever Facts

Some important comments about fever:

It's very important to understand that a fever is a normal response of the body to foreign invaders like bacteria and viruses. The body recognizes a foreign invader and the brain acts to increase body temperature to make things unsuitable for the foreign invader. Most bacteria can only tolerate a certain temperature range and once outside of it, do not survive. It's important to understand that fever is not the result of damage to the body by germs; the body creates fever in response to exposure to germs. Fever has been shown to increase levels of antiviral substances the body produces and also minerals like copper and zinc, the combination of these and other changes help the body's immune response ward off infection.

Normal temperatures and places to take them:

Normal body temperature can be misleading; different areas of the body are different temperatures. For example, the liver is usually in the 105F or above range, which is essential for certain enzymatic reactions that take place like detoxification of chemicals. Skin temperature is usually much cooler, in the 92-95F range. Ask anyone what normal body temperature is and they'll surely respond 98.6 F. But that is only an average taken from a normal range that the majority of the population falls into. There are some exceptions. The normal temperature range for most people is 96.0F - 99.6F. Your temperature is normally lowest in the morning and highest between 4p.m. and midnight. During ovulation in the female the temperature peaks, and during pregnancy it is slightly higher than normal. Children's temperatures are also variable due to their small body size and activity level. Temperatures can be taken orally with a mercury thermometer, usually taken under the back of the tongue for 3-5 minutes. This is the standard place for temperature taking, You may take the temperature rectally with the same instrument, but rectal temperatures are usually one degree higher than oral. This represents a temperature closer to body core temperature. Axillary region, or under the arm, is the least accurate area. It is usually 1F cooler here compared to orally. A good general rule is if taken rectally, subtract one degree and if taken under the arm add one degree. Ear canal temperatures can also be taken with an infrared probe. These devices have become very popular. One potential problem is if an existing ear infection/condition (otitis media) is present, it could give false information. The best way to take ear temperatures is to take three readings and average the readings.

What's a high fever and what are the dangers?

A fever is any temperature between 99.6 - 105F. Fever that results in brain damage is a fear that many parents have, but this concern is not warranted. The body won't let a fever get too high from an infection unless there has been damage to the temperature regulator or "thermostat" of the brain, the hypothalamus. Damage to the hypothalamus can occur from a brain infection (meningitis or encephalitis), or a poisoning. When the weather turns warmer, there is a danger of heat exhaustion and heat stroke. During heat stroke, the body loses the ability to cool itself and control body temperature, and brain damage can result. It is very important to remain well hydrated and cool during extreme temperatures. Another major concern for parents are febrile seizures (convulsions). Seizures occur in 2-6% of children with high fevers. It is thought that these seizures are the body's protective mechanism against rising fevers, like a circuit breaker. Although they can be quite traumatic to parents, they are not the result of, nor do they cause damage to the nervous system. It is very rare for a fever to go above 105F unless there has been damage to the brain.

Treatment of fevers:

Any treatment with a main objective of lowering a fever is generally a mistake if the fever is not very high (over 105F.) Most moderate to high fevers (up to 105F) rarely last more than 3-5 days and can usually be allowed to "run their course." A doctor or parent who worries about bringing down a fever is like a fireman who tries to turn off the fire alarm rather than fight the fire. Fever is a symptom of illness, and suppression of a fever does not make an illness go away. The child should be checked for dehydration and be allowed to rest. Vomiting and diarrhea can cause dehydration, which makes it harder for a body to maintain a stable temperature at high levels. Fluid and electrolyte replacement should be used if this is the case. Excessive bundling, or wrapping of a child should not be done as this could interfere with normal body temperature regulation and could lead to heat exhaustion and even heat stroke. Suppression of fever with aspirin in children is not recommended due to risk of developing Reye's syndrome. Further, long-term acetominophen and ibuprofen use has been found to cause liver and kidney damage. This article is intended to be educational and informative in nature and is not a substitute for medical evaluation and examination.

SOURCES: Victor G. Strang D.C. Ph.C.; Robert Mendelsohn M.D.

Medline articles on Fever

  • Parents' fear regarding fever and febrile seizures. van Stuijvenberg M, de Vos S, Tjiang GC, Steyerberg EW, Derksen-Lubsen G, Moll HA. Department of Paediatrics, Sophia Children's Hospital, Rotterdam, The Netherlands.
    Acta Paediatr 1999 Jun;88(6):618-22

    In order to improve the effectiveness of information, we studied parents' perceptions and knowledge about fever and febrile seizures. A questionnaire study was carried out among the parents whose children (n = 230) participated in a randomized controlled trial of ibuprofen to prevent recurrent febrile seizures. Of the 230 parents, 181 (79%) responded to the questionnaire. Of all parents, 45% were afraid or very afraid of fever, which was strongly associated with being afraid of recurrent febrile seizures. Parents of children with a non-West European background were more afraid. The consequences of parental fear included frequent temperature measurements (25% measured five times per day or more), sleeping in the same room (24%) and 13% remained awake at night. Witnessing a febrile seizure is a frightening experience for parents; a majority thought that febrile seizures were harmful, because they look dangerous. Forty-seven percent thought that their child was dying during the initial febrile seizure. On the other hand, reassuring information may be helpful: 21% mentioned it as their reason to consider febrile seizures not harmful. We conclude that parental fear of fever and febrile seizures is a major problem with several negative consequences for daily family life. Adequate provision of information may reduce parental fear. We suggest that information about fever and febrile seizures should be provided to all parents, preferably during their contact with the providers of preventive healthcare. The parents of children with a non-West European origin need extra attention.

  • Technical report: treatment of the child with simple febrile seizures.
    Baumann RJ
    Pediatrics 1999 Jun;103(6):e86

    OVERVIEW: Simple febrile seizures that occur in children ages 6 months to 5 years are common events with few adverse outcomes. Those who advocate therapy for this disorder have been concerned that such seizures lead to additional febrile seizures, to epilepsy, and perhaps even to brain injury. Moreover, they note the potential for such seizures to cause parental anxiety. We examined the literature to determine whether there was demonstrable benefit to the treatment of simple febrile seizures and whether such benefits exceeded the potential side effects and risks of therapy. The therapeutic approaches considered included continuous anticonvulsant therapies, intermittent therapy, or no anticonvulsant therapy. METHODS: This analysis focused on the neurologically healthy child between 6 months and 5 years of age whose seizure is brief (<15 minutes), generalized, and occurs only once during a 24-hour period during a fever. Children whose seizures are attributable to a central nervous system infection and those who have had a previous afebrile seizure or central nervous system abnormality were excluded. A review of the current literature was conducted using articles obtained through searches in MEDLINE and additional databases. Articles were obtained following defined criteria and data abstracted using a standardized literature review form. Abstracted data were summarized into evidence tables (Tables 1 through 7). RESULTS: Epidemiologic studies demonstrate a high risk of recurrent febrile seizures but a low, though increased, risk of epilepsy. Other adverse outcomes either don't occur or occur so infrequently that their presence is not convincingly demonstrated by the available studies. Although daily anticonvulsant therapy with phenobarbital or valproic acid is effective in decreasing recurrent febrile seizures, the risks and potential side effects of these medications outweigh this benefit. No medication has been shown to prevent the future onset of recurrent afebrile seizures (epilepsy). The use of intermittent diazepam with fever after an initial febrile seizure is likely to decrease the risk of another febrile seizure, but the rate of side effects is high although most families find the perceived benefits to be low. Although antipyretic therapy has other benefits, it does not prevent additional simple febrile seizures. CONCLUSIONS: The Febrile Seizures Subcommittee of the American Academy of Pediatrics' Committee on Quality Improvement used the results of this analysis to derive evidence-based recommendations for the treatment of simple febrile seizures. The outcomes anticipated as a result of the analysis and development of the practice guideline include: 1) to optimize practitioner understanding of the scientific basis for using or avoiding various proposed treatments for children with simple febrile seizures; 2) to improve the health of children with simple febrile seizures by avoiding therapies with high potential for side effects and no demonstrated ability to improve children's eventual outcomes; 3) to reduce costs by avoiding therapies that will not demonstrably improve children's long-term outcomes; and 4) to help the practitioner educate caregivers about the low risks associated with simple febrile seizures.