If I don't have an ear thermometer how best should I take their temperature? Under the arm, in the mouth...

There are many ways of measuring a temperature: by mouth, under the arm, in the ear or in the rectum. Knowing how best to take your child's temperature when you are worried she may have a fever can be very confusing, especially with all these methods as well as all the products available on the market these days. You are looking for something quick, easy and reliable and there is so much to choose from!

Unfortunately the jury is still out on the overall best method to take a child's temperature at home, but to try and get a clearer idea of which method would suit you best take a look: these are the recommendations of the National Institute for Clinical Excellence (NICE)[i] for the use of thermometers to measure fever in children aged 0 to five years mainly.

First, although studies suggest that these techniques are still the gold standard, it is important to establish that taking a temperature my mouth or rectally at home is not recommended by NICE in the 0 to 5 year age group. Equally the use of mercury thermometers should be avoided for the risk of breakage of the thermometer and poisoning with the mercury.

In very small babies, under the age of four weeks, temperature should be measured with an electronic thermometer under the arm (looks a bit like a fine pencil with a plastic cover linked up to a small box-shaped machine), although this kind of thermometer may be hard to find in your local chemist and is mainly used in hospital.

In older children, between the ages of 4 weeks and 5 years, there are three options for measuring temperature:

1. An electronic thermometer under the arm (as described above)

2. A chemical dot thermometer under the arm: Tempadots. These are like very thin strips of plastic with dots on one end that change colour with temperature from blue to brown; they are also very sensitive, accurate and extremely easy to use.

3. An infra-red tympanic thermometer (the ear thermometer). This is often the preferred method because of its ease. Although it is thought to be sensitive to temperatures above 37.5c and can be trusted even when there is an ear infection, it is also thought to not be as accurate (indeed sometimes unreliable) as other methods of measuring temperature, often under-diagnosing fever.

Forehead thermometers are unreliable and should not be used to measure your child's temperature.

Although most fevers in children are self limiting and not sinister it is important to seek your doctor's advice if you are not sure or if any feature in your child worries you.

[1] Feverish Illness in Children: Assessment and initial management in children younger than five years. NICE Clinical Guideline 47 developed by the National Collaborating Centre for Women's and Children's Health, issue date May 2007.