Cold sores causes

Cold sores are caused by the herpes simplex virus.

Once you’ve caught the herpes simplex virus, it can stay in your body for life and cause cold sores to break out up to several times a year.

The virus ‘sleeps’ in the nerves of the skin, and can flare up when your child has other illnesses or sunburn or is tired or stressed. It can also flare up when older girls have periods.

Cold sores symptoms

Your child might complain of an itching, tingling or burning sensation around the mouth, lips or nose. Tiny blisters might appear soon after. These usually crust over in 2-3 days, but can become quite painful and interfere with eating and drinking.

Cold sores generally go away after 7-10 days. Some children tend to get cold sores several times a year, usually in the same place.

The first herpes simplex viral infection in children is often mild, and in some children it doesn’t even have symptoms. In other children, the first infection might cause lots of cold sores in the mouth, with associated fever and pain. This is referred to as a herpes simplex mouth infection (gingivostomatitis).

When to see your doctor about cold sores

You should take your child to the GP if:

  • the cold sores are weeping or starting to spread – this might mean your child has a secondary or bacterial infection and needs antibiotics
  • your child has a fever as well as cold sores and is generally unwell
  • the cold sores make it hard for your child to drink fluids even after you give your child pain relief (this might lead to dehydration, especially in younger children.

Cold sores treatment

Cold sores usually clear up within 7-10 days without specific treatment. But if you have any concerns, you should see your doctor. If your child is really uncomfortable, some paracetamol in recommended doses can help to ease the pain.

Your doctor might recommend povidine-iodine ointments (for example, Betadine®) or anti-viral ointment like aciclovir (for example, Zovirax®). These ointments can help cold sores go away faster if you apply it very early, at the first sign of infection when the area is tingling.

Some children with very severe or very frequent cold sore outbreaks might be prescribed anti-viral medication to reduce how often outbreaks happen and how long they last.

Most children with cold sores can eat and drink normally, but some children have pain that stops them from eating and drinking normally. As well as giving your child pain relief, you should gently encourage your child to drink. You can also give your child oral rehydration solution, which you can get as liquid or in ice blocks from any pharmacy.

Cold sores prevention

Cold sores are highly contagious, so avoid kissing contact with infected people.

If it’s practical, try to avoid things that trigger cold sore outbreaks in your child. For example, you might try to avoid your child getting overtired or sunburned.