Fever in babies: what to do and when to seek advice

Fever is the main reason for visits to paediatric emergency departments, because of the alarm it causes in parents, especially the younger the baby is. That is why our team of midwives at Happymami have prepared the following post for you on the latest update on baby fever available.

What is fever?

It may seem odd, but fever is one of the defences that your baby's body has against different germs. It uses it to fight them off: your baby's body tries to reach a temperature higher than usual. Therefore, fever helps to defend against illness.

How do we know if your baby has a fever?

It is important that you always measure fever with a thermometer and not by touch. We consider that your baby has a fever when their body temperature is above 38 °C in the rectum or 37.5 °C in the armpit. Measured in the armpit, it is considered a moderate fever up to 39 °C, and above 39 °C we will talk about a high fever.

What causes fever in a child?

There are many possible causes, but viral, acute and benign infections are the most common cause of fever.

• Respiratory infections: Usually mild, of no consequence, viral, and they usually clear up without medical treatment. The fever may be accompanied by a cough and a runny nose. Babies stay in a good general condition when they have no fever and look listless when it comes back.
• Gastrointestinal infections: We will recognise them because they usually come with vomiting, diarrhoea or abdominal pain.
• Urinary tract infections: They may appear only with fever and no other symptoms; at other times, they may be accompanied by vomiting and refusing food.

Other causes of baby fever

• Vaccinations: After being vaccinated, babies may also develop fever.
• Teething: Although it is a matter of debate, it can cause a slight rise in temperature, which usually does not exceed 38 °C. •
• Too many layers: Newborns are not able to regulate their temperature at first, so if we wrap them up too much or keep them in hot environments, they can develop fever. What you should do as parents before raising the alarm is to unwrap your baby and take their temperature again. If the fever persists, you should see the paediatrician so that they can examine your baby. If there is no fever and it was a false alarm, you should keep an eye on the general condition of your baby and stay alert in case the temperature rises again.
• Other, less frequent causes: Dehydration and some types of poisoning are worth remembering.

Does “a high fever” mean “a serious illness”?

It is a very common question, and the answer is: not always. Let me explain: body temperature is not always proportional to how serious the cause is. A severe infection may barely cause a few tenths of a degree, while a cold, in principle harmless, may come with fever of up to 40 °C. The most important thing is to determine what is causing the fever. It is therefore essential to watch carefully the symptoms shown by your baby.

What is a raised temperature?

The following table shows the temperature values classified according to the severity of the fever.

36.0 °C to 37.0 °C	Normal human temperature
37.1 °C to 38.1 °C	Low-grade fever
38.1 °C to 38.5 °C	Mild fever
38.5 °C to 39.0 °C	Moderate fever
From 39.0 °C	High fever

Where should I take my child's temperature?

Although stroking your baby's skin may seem enough to suspect that they have a fever, this method is very non-specific and does not give a reliable temperature reading. Taking the temperature of a baby who will not stop moving can be very difficult for parents, so a different type of measurement is advised depending on age. If your baby is under 3 months old, the best option is to measure the rectal temperature with a digital thermometer.

Many parents are afraid of not doing it properly or of hurting the baby if they move, so you can lubricate the tip of the thermometer with a lubricating gel to make it easier to insert into the anus. Electronic ear thermometers are not recommended for babies under 3 months old because their external ear canals are too small. If your baby is between 3 months and 3 years old, a digital thermometer can be used to measure the rectal temperature.

You could also use a digital thermometer to measure the armpit temperature, although this method is less accurate. The oral temperature and tympanic temperature (in the ear) should not be used in babies under 2 years old and, if they are used afterwards, you need a lot of experience in using them. If your child is already 3 years old and can cooperate, a digital thermometer can be used to measure the oral temperature.

If your baby has a cough or nasal congestion and cannot keep their mouth closed for the time needed to take the reading, the best option is to use the armpit method (with a digital thermometer). You can use the tympanic method (with an electronic ear thermometer), for which, as we have said, you need to have experience.

What type of thermometer should I use to take my child's temperature?

Although some are no longer used, we will mention the following:

• Digital thermometers: They measure fever quickly and safely. They are easy to use and easy to read.
• Mercury thermometer: Despite being reliable in terms of measurement and being the traditional method, its sale has been banned as it is potentially dangerous because of the mercury it contains, so it is advisable to use one of the other methods.
• Ear thermometers: These are electronic thermometers that measure temperature from inside the ear canal. Their measurement is not as accurate when used on very young children, and they are more expensive.
• Dummy thermometer: They look like a conventional dummy and have a digital screen that parents have to look at to see the temperature. The measurement is not reliable.
• Plastic strip thermometers: This is a device that is placed on the forehead and gives unreliable temperature readings.

Who should you consult if your child has a fever?

If you have any doubt about your baby's state of health, you should always consult the paediatrician. Your paediatrician will see you, try to answer any questions you may have and give your baby the correct and most effective treatment.

How do we treat fever?

As always, the most important thing is to treat the cause behind it; the treatment of the fever itself will be carried out depending on the temperature range your baby has. Bear in mind that it is the paediatrician who should assess it.

• Low-grade fever (up to 38 °C): Treatment is not recommended. We should not overuse medicines that reduce fever (antipyretics), especially if your baby is well. What you should do is offer plenty of fluids and keep them cool with little clothing on. If the discomfort does not stop and the fever continues, you should go to your paediatrician so that they can assess your baby.
• Fever (from 38 °C): Treatment with antipyretics according to the doses prescribed by the paediatrician can be complemented with plenty of fluids, damp cloths on the forehead (at room temperature, never too cold and never with ice), as well as lukewarm baths for 15 or 20 minutes. If the temperature stays above 39.5 °C, a further assessment by the paediatrician may be advisable.

Questions parents ask when giving fever medicine (Always follow the paediatrician's instructions.)

• What is better: the same antipyretic all the time, or alternating two different antipyretics? Antipyretics reduce fever and therefore relieve and improve the general condition of your baby. However, they do not act on the cause of the illness and in no case do they cure it or shorten its duration. The doses should not be doubled, and several medicines for fever should not be used at the same time. Alternating them is not advisable either. Contrary to what you might think, this practice does not increase effectiveness and, on the contrary, carries serious risks of poisoning.
• How should the antipyretic be given: orally or rectally? Under normal conditions, it is better to use the oral route rather than the rectal one, but sometimes the baby vomits when they have a fever and is unable to take the antipyretic. In this case, one solution would be to give it rectally.

• Can baths replace the antipyretic? No. The main measure to control fever is to give an antipyretic and unwrap the baby. As a complement, and in certain circumstances (high fever, which comes back quickly…), baths or compresses on the forehead can be used, but always keeping up the antipyretic according to the established schedule. A bath is especially useful after giving the antipyretic if the fever is very high, as it will help bring the temperature down while the medicine takes effect. It is advisable:
  • For the bath water to be at a temperature close to that of the baby (not cold).
  • For it to be long (15-20 minutes), so that as the water cools, their temperature comes down too.
  • It is also recommended to rub the body with a sponge to encourage heat loss.
• And antibiotics, do they help to bring down a fever? Antibiotics will help to stop the infection if it is bacterial. As the infection eases, the fever will gradually disappear. In the case of a viral infection (the most common), antibiotics are not useful, the infection will continue, so the fever will persist. It will be your paediatrician who assesses whether your baby's infection is viral or bacterial and who therefore decides whether the use of antibiotics is justified.
• When should you consult the paediatrician? The first thing we should do before consulting our paediatrician is to look at how your baby seems: if, despite the fever, they are happy, eating well and drinking plenty of fluids, we should not be alarmed, as it is unlikely to be anything serious. You should consult if your baby:
  • Is under 2 years old (especially under 3 months).
  • Is listless and drowsy.
  • Is irritable.
  • Has a significant headache and/or vomiting.
  • Is struggling to breathe.
  • Has a seizure.
  • Has small red spots (cherry-coloured) or black patches on the skin.
  • Seems generally unwell.
  • Has fever of 40 °C that does not come down despite treatment with antipyretics.
  • Babies with a neurological condition.

In conclusion, baby fever, what should you do?

As we always tell you, every case is unique, so you should adapt this information to your own situation. But yes, do bear in mind the most important tips from this post on baby fever, what should you do?:

• If you have any doubt about your baby's state of health, always consult the paediatrician.
• We will detect fever with a thermometer and not by touch.
• Your baby has a fever if their body temperature is above 37.5 °C in the armpit or 38 °C in the rectum.
• Up to 39 °C it is a moderate fever; above 39 °C it is considered a high fever.
• Most often, the fever is caused by a benign acute viral infection.
• “A high fever” does not always mean “a serious illness”. Fever is only a symptom. The important thing is to determine what is causing it.
• You should take into account both the temperature and the general condition of your baby.
• Several antipyretics should not be combined, and you should not exceed the frequency or the dose established by the paediatrician.