Questions from practice: Monitoring fever in young children
QuestionsI think my little boy has a fever. What should his temperature be? Do I need to call the doctor?
A child is usually regarded as having a fever if his or her temperature is 38C or above. Body temperature can be measured in the mouth, ear, armpits and rectum, or on the forehead.
Where to measure
The oral and rectal sites give the most accurate measurements of core temperature, but the latter is not recommended because it can lead to bowel perforation and it can be unacceptable to patients.
Measurements in the armpit usually underestimate core temperatures by at least 0.5C, although this difference is smaller in babies. In older children the two values may vary by up to 2C. Temperatures taken in the ear may under- or overestimate body temperature by 0.3C.1
Because core temperature can be affected by age, time of day and exercise as well as illness, it can be useful for parents to establish their child’s temperature when he or she is well so that a fever can be more easily identified.
Type of thermometer
Many different types of thermometer are available. Digital thermometers are rapid, inexpensive and can be used either in the armpit or mouth.
Ear thermometers give rapid, accurate readings, but are expensive and should be used with disposable probe covers for hygiene. They should be used according to manufacturer’s instructions. Aural readings can be influenced by factors such as lying on or covering an ear, and hot or cold weather. In such cases, the child’s temperature should be measured after 20 minutes so the ear properly reflects body temperature.
A child with an ear infection will have a raised aural temperature due to inflammation so readings should be taken from the other ear.
The temperature of a child’s forehead can also be measured with a handheld forehead thermometer or a forehead strip. These have the advantage of being non-invasive but, according to the National Institute for Health and Clinical Excellence, forehead strips are less reliable than other methods and are not recommended.1
Mercury thermometers are not suitable due to the risk of breakage and mercury exposure. The oral route should be avoided in children under five years old because it may be uncomfortable, and younger children may bite the thermometer.
NICE guidance from 2007 recommends the following methods for measuring body temperature in young children:
- Electronic (digital) thermometer in the armpit for babies under four weeks old
- Electronic thermometer in the armpit or infrared ear thermometer in children aged four weeks to five years
Presumably, after the age of five years, oral or aural readings are probably the methods of choice because they are likely to be the most accurate.
When to refer
Fever is common in childhood and is mostly associated with self-limiting viral infections. In some cases, however, it can be an indication of a more serious underlying infection, such as pneumonia or meningitis, which would require immediate referral to an accident and emergency department.
Pharmacists should ask about alarm symptoms such as difficult or rapid breathing, drowsiness, abnormal skin colour or a non-blanching rash, weak or high pitched cry or continuous crying, neck stiffness and a bulging fontanelle.
Some young children may suffer a seizure when feverish. All children who fit should be referred to casualty on the first occasion or if the seizure lasts more than five minutes.1 Parents of a child who has a fit lasting less than five minutes should seek advice from their GP.
Infants under three months of age with a temperature of 38C or aged between three and six months with a temperature of 39C are at high risk of serious illness so should be referred to a GP.1
Babies who are feeding poorly or have decreased numbers of wet nappies should be referred because of the risk of dehydration.
Other causes of fever include immunisations, ear, throat, chest, or urinary tract infections, and childhood infections, such as chickenpox and measles, and may require GP referral.
The necessity of treating a fever is much debated. Some see fever as a normal response to infection that may be beneficial and children who have a fever but are otherwise well may not need antipyretics. However, if a child with fever is unwell or is distressed paracetamol or ibuprofen may be given.
Clinical Knowledge Summaries2 and NICE consider each agent equally effective but a recent National Institute for Health Research Health Technology Assessment programme study (PITCH) suggests that ibuprofen should be first choice because it results in a slightly more rapid resolution of fever and a longer period without fever than paracetamol.3
Ibuprofen may be more useful at night because of its longer duration of action. The HTA study also found paracetamol and ibuprofen to have similar safety profiles.
If one drug appears ineffective (and alarm symptoms are absent), the pharmacist should check the doses being given. If recommended dosing has been complied with, switching to monotherapy with the other agent can be considered.
Using both agents (paracetamol every four to six hours, to a maximum of four doses in 24 hours, and ibuprofen every six to eight hours, to a maximum of three doses in 24 hours, meaning that the two drugs could be given together or separately) is acceptable where switching has failed.
The HTA study showed that paracetamol plus ibuprofen resulted in a longer time without fever than either agent alone. However NICE has expressed concern that using the two drugs in this way carries a risk of overdosage (as well as underdosage), and the HTA study found that 8–11 per cent of parents exceeded the maximum daily doses of the two drugs in 24 hours.
Carers should, therefore, be reminded of maximum daily doses and advised to keep a record of doses administered. NICE is also concerned that the combination may be linked to an increased incidence of adverse effects.
If none of the referral criteria applies, this mother can be reassured that fever is normal and common in young children, and that most recover quickly without problems. She should be advised to give the child plenty of fluids, check his condition during the night (since deterioration can be rapid) and seek medical advice if her son’s condition worsens, if he develops any alarm symptoms, or fails to improve within five days.
Tepid sponging or lukewarm baths should not be used to reduce a child’s temperature because they can cause distress and peripheral vasoconstriction (limiting heat loss) and shivering (increasing heat).1
Children should be clothed so that they neither overheat nor shiver and kept away from school or nursery until the fever resolves.
— Sarah Marshall, freelance pharmaceutical writer from Aberdeenshire
1 National Collaborating Centre for Women’s and Children’s Health.2007. Feverish illness in children. Assessment and initial management in children younger than 5 years (full NICE guideline). Royal College of Obstetricians and Gynaecologists (accessed on 20 September 2010)
2 Clinical Knowledge Summaries. Feverish children — management (accessed on 20 September 2010).
3 Hay AD, Redmond NM, Costelloe C Montgomery AA, Fletcher M, Hollinghurst S et al. Paracetamol and ibuprofen for the treatment of fever in children: The PITCH randomised controlled trial. (PDF 100K) Health Technology Assessment 2009;13 (27)
Citation: The Pharmaceutical Journal URI: 11046537
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