Causes and Risk Factors for Elevated Body Temperature in Infants
A fever, or elevated body temperature, typically indicates that the immune system is functioning effectively as the body combats an illness. Therefore, a fever is not a standalone disease but rather a symptom of an underlying condition. Although fever is a natural response, it can cause discomfort and distress in infants, increasing their heart rate and respiratory rate while enhancing their need for hydration. The common reasons for elevated body temperature in infants include:
Infection
Infections are among the most prevalent causes of fever in infants. A rise in body temperature activates the body’s natural defense mechanisms, assisting in the fight against infections. Newborns and young infants are particularly susceptible to certain severe infections due to their underdeveloped immune systems. In reality, there are hundreds of bacteria that cause infections, with viruses being more common culprits than bacteria. Viral infections such as the common cold and influenza are among the leading causes of fevers in infants, often being the sole symptom observed within the first 24 hours of exposure to the virus. Other symptoms like nasal congestion and coughing may appear later. For instance, in cases of roseola, fever may be the only noticeable symptom for two to three days following infection before a rash develops.
It can be said that almost all instances of elevated body temperature in infants are due to new infections, which may be acquired during or prior to birth. Children born to mothers with Group B Streptococcus infections are at greater risk of developing fever due to serious bacterial infections. Likewise, infants born prematurely or those with chronic conditions, such as heart diseases, are at increased risk. It is important to note that any infant under three months of age with a fever represents a critical situation, as the fever may stem from sepsis, a severe bacterial infection affecting the bloodstream. Given how rapidly bacterial infections can worsen at this age, it is crucial for healthcare providers to evaluate and treat affected infants promptly.
Additionally, respiratory infections, such as respiratory syncytial virus (RSV), croup, and viral throat infections, commonly lead to fevers in infants. Streptococcal throat infections are also recognized causes of unexplained fevers. Though less common, other serious conditions such as pneumonia, urinary tract infections, ear infections, and severe infections like septicemia and meningitis—an infection of the protective membranes covering the brain and spinal cord—can also cause fevers. Symptoms of meningitis include headache, neck stiffness, and confusion.
Overdressing and Hot Weather
Infants, especially newborns, can experience fever as a result of being excessively overdressed or exposed to hot environments. Unlike older children, they are less capable of regulating their body temperature. However, if an infant, particularly a newborn, presents with fever, it is essential to consult a physician as it may indicate a serious infection. Notably, infants have a lower efficiency in temperature control compared to adults, making them more vulnerable to extreme heat. They could experience elevated body temperatures indoors if they are located near heaters or other heat sources, or within cars where temperatures can rise rapidly. It is critical never to leave a child alone in a closed vehicle, even for a minute, as this can quickly lead to heatstroke or fatality.
Vaccinations
It is normal for infants to experience a slight fever following vaccinations. This response is benign and indicates the vaccination is functioning as intended. Typically, temperature elevations begin within 12 hours following vaccination and may last from a few hours to two or three days. Certain vaccinations, such as the measles vaccine, can cause a temperature increase lasting up to a week or two post-administration. It is important for parents to continue vaccinating their children on schedule, provided the fever remains mild and no serious illnesses are present.
Fluid Deficiency or Dehydration
Some infants may not receive sufficient fluid intake, leading to an increase in body temperature. For newborns, inadequate breastfeeding or formula intake can also elevate their temperatures. Dehydration can occur if these fluids are not replenished, leading to severe health complications. In such cases, intravenous fluids may be necessary to address dehydration.
Other Causes
Infants may also develop a fever following skin injuries, often indicating an infection. While fever caused by heat-related illnesses is rare in infants, other potential causes of elevated body temperature include:
- Administration of certain medications, such as antibiotics, anticonvulsants, and blood pressure medications.
- Autoimmune disorders, which occur when the body’s immune system mistakenly attacks its own healthy tissues.
Things That Do Not Cause Fever in Infants
Many children experience fever around the time of teething, coinciding with their immune systems maturing. However, teething is not responsible for elevated temperatures, as it does not lead to fever. Rather, the body may be fighting off other issues. While it is challenging to completely dismiss this notion, it is important to note that a body temperature above 38.9 degrees Celsius should not be attributed to teething; other underlying causes must be investigated.
When Is an Infant’s Temperature Considered Elevated?
Elevated body temperature or fever in infants does not necessarily imply the presence of a serious illness, provided the child’s behavior and activity levels remain normal. The severity of fever does not always correlate with the seriousness of the illness. Infants usually exhibit higher body temperatures than adults due to their more active metabolism, which generates more heat. However, a healthcare provider should always be consulted if an infant under three months of age presents with a rectal temperature exceeding 38 degrees Celsius. The method of measuring temperature plays a crucial role in determining fever, as outlined below:
- Rectal thermometer: A temperature is considered elevated if it exceeds 38 degrees Celsius.
- Axillary (armpit) thermometer: A temperature is elevated if it surpasses 37.22 degrees Celsius.
- Oral thermometer: A temperature higher than 37.78 degrees Celsius is regarded as elevated, although this method is often inaccurate for infants.
For more information on normal infant body temperature, consider reading the following article: (What is the Normal Temperature for Infants).
For additional insights on fever in infants, please refer to the subsequent article: (Fever in Infants).
Preventing Elevated Body Temperature in Infants
Preventative measures against elevated body temperature include avoiding known causes of infections and illnesses, especially when a rise in temperature is linked to a specific infection. If fever results from vaccinations, administering acetaminophen may help; it is an over-the-counter medication that can be provided before or immediately after vaccination. Importantly, consult a healthcare professional before giving any medication to infants under two months of age. To reduce the risk of fever in infants, consider the following recommendations:
- Maintain the room temperature between 22-24 degrees Celsius.
- Keep the child away from heating sources, including heaters, open flames, and direct sunlight.
- Dress the child in appropriate and comfortable clothing for the weather; infants do not require more layers than adults. When traveling by car, ensure that the child is dressed suitably, since cars can heat up rapidly.
- Limit outdoor activities during extremely hot weather and keep infants sheltered from direct sunlight to help regulate their body temperature.