Stay calm, don’t panic! Fever is a sign of illness and is not an illness in itself. Fever alone is not dangerous. Contrary to wide belief, fever almost never causes permanent brain damage, even high fevers of 105° to 106° F. In fact, we are not aware of any reports in the medical literature of brain damage occurring with fever alone as the cause.
While it’s true that very, very high fevers, with a body temperature of 107°F or higher can cause brain damage, this is an extremely rare event in children. Fever at this extreme is usually seen in disorders such as malignant hyperthermia, a brain disorder that is sometimes caused by anesthesia, or with heat stroke or heat exhaustion in which the child is in a hot environment that overwhelms their ability to cool themselves resulting in the accumulation of body heat. Malignant hyperthermia and heat stroke are not covered here in this webpage. These conditions require immediate treatment at an emergency room.
Fever should be viewed as the body’s normal response to fighting infection. Fever is caused by “pyrogens” which are substances released into the blood stream by the body’s white blood cells as they attack invading bacteria or viruses. The brain senses these pyrogens and causes the body’s temperature to rise (shaking, chills and increased heart rate). Thus, fever is actually a signal to the rest of the body’s white blood cells that there is an infection present and that they should fight harder. They respond by fighting much harder than they do at normal temperatures. Therefore fever is the normal response of the body to infection. With fever, bacteria and viruses are killed more efficiently. Chicken pox for instance is less severe if the fever is not treated (less lesions, less scarring, shorter duration of illness). This is the case for all infectious illnesses; fever is beneficial.
In summary, fever alone caused by the normal infections that kids get, usually between 101° to 104° F, is not dangerous.
The problem that fever presents is determining how severe the infection is that is causing it. The vast majority of fever-associated illnesses are caused by trivial viral infections which are short-lived and not at all serious. Many times the severity of the illness is not related to the degree of temperature elevation. What we mean by this is that trivial fever virus infections may cause high fevers and these are not serious. Because of these considerations, fever alone should not be a cause of alarm and is almost never an emergency.
In order to determine the seriousness of a fever associated illness, we have developed the following approach for our patients with fever. This approach is not directed at treating the fever because it is dangerous by itself, but instead is aimed at determining the seriousness of an illness which has fever as a sign. How your child is acting is a much more important sign of the seriousness of the illness than is the degree of fever. You should carefully follow the steps we have laid out in the section below to determine what your course of action should be. Our approach to fever is based on associated symptoms of the child and the fact that the fever caused by most trivial viral infections will be short lived and easily brought down. Please remember that you are treating fever to determine the seriousness of the illness and for comfort’s sake. Because serious illnesses do cause fever, your following our advice in this section may be crucial to your child’s health.
How to take your child’s temperature
If you feel your child has a fever, take their temperature. The temperature may be taken with:
- a digital thermometer: in the rectum, under the tongue (oral), or under the arm (axillary)
- an ear (tympanic) thermometer
- a temporal artery scanner.
Note: We do not recommend temperature strips on the forehead. Also old mercury thermometers are not recommended because of mercury toxicity if they break.
Rectal digital thermometer
For children under three years of age, the rectal temperature is the most accurate and simplest to take. We recommend digital thermometers. These can be purchased for a minimal amount of money at most discount stores. You can also purchase a box of cellophane sleeves for the rectal digital thermometer for cleanliness sake. Take the temperature by lubricating the thermometer with petroleum jelly (Vaseline) and inserting it into the child’s rectum approximately one inch. Remove the thermometer after the temperature has registered. Fever is defined as a temperature above 100.5° F taken rectally.
The rectal temperature is usually one degree higher than an oral and two degrees higher than an axillary temperature. Axillary temperatures are the least accurate way of measuring temperature. You should note the actual temperature and note the method used.
Tympanic (ear) thermometer
Tympanic (ear) thermometers are very quick, painless and accurate in measuring temperature for children over the age of six months. Ear thermometers are inaccurate in very young children and should not be used during the first six months of life. The device is actually an infrared camera that takes an infrared “picture” of the eardrum and calculates the temperature from that picture. To take the temperature, place the probe in your child’s ear after you have gently but firmly pulled the ear upwards and backwards to straighten out the ear canal. Point the probe of the thermometer at the opposite ear and then press the button down for one second. Fever taken in this fashion is defined as a temperature above 100.5 degrees Fahrenheit. Normal temperatures for children taken in this fashion are 96.4 to 100.4 degrees Fahrenheit.
Temporal artery thermometer
Temporal artery thermometers have also been shown to be accurate and very easy to operate. They scan the temperature of the skin around the temporal artery (temple region of the skull). To obtain the temperature position the probe flat on the center of the forehead and then press and hold the scan button. Lightly slide the thermometer across the forehead, keeping the sensor flat and in contact with the skin of the forehead. Scan until you reach hairline (temporal area). These scanners are expensive, but accurate. Fever is defined as a temperature above:
- 100.7° F for babies 0 – 2 months
- 100.3° F for chidden 3 – 47 months
- 100.1 for kids 4 years of age – adulthood
Treatment of Fever:
- Give acetaminophen (such as Tylenol, see Dosing Guide).
- Dress your child in loose fitting clothing such as a T-shirt and under wear or a diaper. Do not bundle your child tightly or cover him with a blanket because this will only make the temperature rise further.
- Give your child cool liquids to drink.
- If your child has a high fever which does not respond to the above measures within 30 to 60 minutes, you may try to lower your child’s temperature by giving him a sponge bath with lukewarm water. Do not use cold water or an alcohol bath. These are dangerous methods to use. To give your child a lukewarm bath, place your child in a tub of lukewarm water and sponge him off thoroughly. You can use a cup and pour water over his head. You can expect your child to shiver and cry vigorously during the sponge bath.
- If you have ibuprofen (Children’s Motrin, Children’s Advil Suspension) you may give it in addition to acetaminophen to relieve fever. There are several liquid forms of ibuprofen which have been approved for children six months of age and older. See Dosing Guide for instructions. We intend for ibuprofen to be used for particularly high fevers, usually above 102 degrees F. These medications are available without a prescription. Acetaminophen and ibuprofen may be given simultaneously, acetaminophen every four hours and ibuprofen every six to eight hours if acetaminophen alone is unsuccessful at relieving the fever. A popular way of using ibuprofen and acetaminophen together is to alternate them every 3 hours: acetaminophen given now, ibuprofen given in three hours and then alternate them every three hours. Ibuprofen should be viewed as the second line drug for fever control, only to be used in addition to acetaminophen if acetaminophen alone is not completely effective at reducing the fever. Please check the dosing guide for proper dose. Please note that the use of ibuprofen is discouraged for the fever of strep infections and Chicken pox, because of a possible link to a severe infection called necrotizing fasciitis. So, in these infections avoid using ibuprofen.
Your Child should be Evaluated When:
- You should call the office during regular office hours if your child has a prolonged fever above 101 degrees F. for more than 48 hours.
- You should call the office during regular office hours if your child has fever plus any sign of a minor infection such as a sore throat, ear ache, pain on urination, significant cough or mild rash.
- More significant symptoms such as breathing problems, severe headache, stiff neck, inconsolable irritability, lethargy, unusual difficulty in waking the child, seizures, a bruise like rash, or any other significant symptom which is unusual for your child associated with fever, demands prompt attention from the physician when they occur.
- Fever above 100.5 degrees F. taken rectally in infants younger than two months is significant even in the absence of other symptoms. This is the only instance of a true emergency with fever as the only sign of illness. The physician should be notified with any such infant with fever and immediately evaluated. Life threatening bacterial infections such as blood infections (sepsis), pneumonia, urinary tract infections and meningitis must be ruled out.
- The physician should be notified with any high fever above 104 degrees F. which is unresponsive to acetaminophen, ibuprofen, and sponge baths. If your child’s high fever comes down with the above measures, then there is no cause for alarm from the fever. High fevers which come down only to recur shortly after the medication has worn off should be evaluated in the office during regular office hours.
Note on the purpose of fever: Once a diagnosis is obtained, fever control is usually not necessary and if done may prolong and worsen the illness. As explained above, fever is part of the defense mechanism of the body and as such is beneficial in fighting off infections. Fever is a physiologic signal to the white bloods cells in the body. They fight much harder in response to the presence of fever. In our practice, we have chosen 102 degrees Fahrenheit, as the temperature at which we would recommend using acetaminophen and/or ibuprofen mainly for comfort’s sake.
We do want to make you aware that febrile seizures (seizures which occur with fever alone as the cause) do occur rarely with fever in young children. It has been estimated that 1 to 4 percent of children will have one or more febrile seizures in their lifetime. Although quite frightening when they occur, febrile seizures are harmless and result in no permanent brain damage. If your child should have a seizure associated with fever, you should take your child to the nearest emergency room. We will evaluate your child to make sure that a more serious condition is not the cause of the seizure. Should your child develop febrile seizures, fever control is needed with any fever associated illness.