Professor Anne MacGregor gives tips for parents on how to recognise and treat headaches in children.
Most children and teenagers get at least one headache a year. They're often different from the headaches that adults get, so parents and healthcare professionals can fail to notice the problem.
Headaches, including migraines, tend to be much shorter in children, according to Professor MacGregor of the Centre for Neuroscience and Trauma at Barts and the London School of Medicine and Dentistry.
They start suddenly in children, with the child quickly becoming pale and listless, and often feeling sick and vomiting.
Children also generally recover very quickly. "The headache can be over half an hour later, with the child feeling well and playing outside as if nothing's happened," Professor MacGregor says.
Children's headaches can also affect their stomach, so a tummy ache is a common complaint, she says.
"In my experience, children very rarely fake headaches," says Professor MacGregor.
"Children with headaches often get them if, for example, they skip their lunch or they haven't had anything to drink all day.
"The best way for parents to prevent their children getting these headaches is to make sure they have regular meals and drinks, and that they get enough sleep," says Professor MacGregor.
"Give children a good breakfast so that, even if they miss lunch, they've been set up for the day. It's also helpful to put children to bed at a fixed time each evening."
Sport can trigger children's headaches, probably because of dehydration and the effect on blood sugar.
"Drinking lots of water and sucking glucose tablets [available from pharmacies and supermarkets] before and during sport can help.
"So can a mid-morning and mid-afternoon snack, as well as meals," says Professor MacGregor.
Sometimes headaches can be the result of emotional problems. "They can come on during times of stress, like being bullied at school or because of anxiety over parents splitting up," says Professor MacGregor.
"Parents often think their child is fine, that they're adjusting to the divorce and that they like their parent's new partner.
"Sometimes, however, the child is not fine and their unhappiness is expressing itself as headaches."
It can be helpful to keep a diary of your child's headaches. If your child is old enough, they can keep their own diary. This is a good way of working out specific headache triggers.
Keep a record of when the headaches happen. Also record any event that's different from the normal routine or that might be relevant.
This could be a missed meal, sports activity or a late night, or an emotionally upsetting incident, such as a stressful exam or an argument with friends or parents.
After a few months, look through the diaries together with your child to see if there's a pattern of triggers that could be causing the headaches.
Once you have identified possible causes, get your child to avoid them one at a time over the next few months to see if this prevents the headaches.
Often, simple steps will be enough to help your child through a headache or migraine attack:
If you think your child needs painkillers, start the medicine as soon as possible after the headache has begun.
Alternatively, ask your pharmacist for medicine that treats migraines and is suitable for children.
As with adults, most headaches in children aren't a serious health problem. They can be treated at home with pharmacy remedies, and be avoided by making sure children get enough food, drink and sleep.
But don't delay consulting a doctor or pharmacist if you're worried about your child's headaches, says Professor MacGregor.
"I'd advise parents to seek help if their child hasn't been helped by painkillers or if the headaches are interfering with schoolwork. It's important for these children to get the all-clear from a doctor."
The Brain Tumour Charity's HeadSmart campaign has information on how to recognise the symptoms of brain tumours in children.
Read more about how to treat common conditions using your local pharmacy.