Fevers can be puzzling and alarming, especially for parents whose young children have them. Though fevers can be a symptom of a more serious problem, they generally illustrate the body’s immune system at work. Over certain temperatures, depending on the person’s age, fevers can be dangerous, so use this guide to learn when to call a doctor.
A fever is when the body’s temperature rises to a certain level of just over 100 F. Although fevers occur primarily as a response to bacterial and viral infections, excessive exposure to the sun, side effects of medication, and certain other health conditions can also cause fevers. The different stages of a fever are characterized by a variety of symptoms, including chills, aches, overheating, and sweating. For many, fevers are an uncomfortable accompaniment to an already bothersome illness. To the very young, however, fevers can be much more dangerous and warrant contacting a health professional.
- A body temperature of 100.5 F or higher, taken rectally, is considered to be a fever. Rectal thermometer readings are about one degree higher than a reading from an oral thermometer. When you’re talking to a doctor, don’t try to convert the readings to oral or rectal, says the Mayo Clinic. Just tell the doctor what the temperature is and specify how you measured it.
- The body’s temperature fluctuates throughout the day, and can rise after exercise, or even when someone is wearing too many clothes. Body temperature tends to be lower in the morning.
For an overview of fevers …
is a service of the U.S. National Library of Medicine and the National Institutes of Health. This article explains that fevers are defense mechanisms used by the human body to fight bacterial and viral infections. Temperatures over 98.6 F can kill organisms that might thrive in that range. Also find advice for when to call the doctor, and how to care for children and adults with fevers at home.
describes the reasons why someone may have a fever, which include having an infection, a reaction to medication, or even sunburn. Learn when to call a doctor about a fever
by age group; when a child of three months or younger has a temperature of 100.4 degrees or higher, call a doctor just to be safe.
is a consumer health portal run by Aetna that draws much of its content from the experts at Harvard Medical School. Access a brief overview of fevers that covers what they are, their causes, symptoms, diagnosis, and treatment.
For fever symptoms …
St. John Health
is a system of hospitals and medical organizations in southeast Michigan. Find a list of the symptoms commonly experienced during a fever, and also how to treat adult fevers.
Fevers that aren’t a symptom of another illness can be monitored and treated at home with over-the-counter medication and plenty of fluids. Fevers typically last for a few days, at the most. However, additional treatment may be needed if the fever is symptomatic of another condition.
- Mercury was once commonly used in thermometers because of its sensitivity to changes in temperature. But mercury poses health risks to children and adults, and it should no longer be used. Be wary of any thermometer containing a silver liquid.
- Don’t give aspirin to children with fevers, as it could cause a potentially fatal condition called Reye’s syndrome. Speak to your child’s doctor about what over-the-counter medications they should take.
- According to MedlinePlus, you should never submerge someone suffering from a fever in a bath of cold water. Although it might feel refreshing at first, the shivering it causes raises core body temperature, exacerbating the fever.
For a quick reference in treating fevers …
has a chart that offers treatment options by age group, from birth to adults 18 years and older.
For treating fevers in children …
has a brief video (less than two minutes) about fevers in children. One pediatrician interviewed said fevers are a good sign the immune system is doing its job, and fevers of 101 F or less shouldn’t be treated. Most fevers, the doctor says, will go away in 24 hours. If a fever of 101 F or less lasts longer, then call the doctor.
The American Academy of Pediatrics
has a chart showing the best way to take your child’s temperature—orally, rectally, or under the arm (axillary)—by age. Also learn how to clean a thermometer, with step-by-step directions for taking a rectal temperature in children under the age of 3, and instructions for taking oral temperatures in older children.
Children’s Hospital Boston
has advice for treating mild fevers in children. Scroll down the page to learn when to call the doctor and to find other advice. Children, for example, should receive plenty of non-caffeinated fluids to keep them hydrated, should be dressed in light clothes, and should be fed even if they aren’t hungry.
For treating fevers in adults …
has a page that describes what adults can do to lower their fevers, by providing comprehensive overviews of at home and professional fever treatments. Some of the advice mentioned includes taking alternating doses of ibuprofen and acetaminophen, and drinking lots of non-caffeinated fluids to stay hydrated.
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