About cold sores

Cold sores are tiny blisters caused by herpes simplex virus.

Once you have herpes simplex virus, it sleeps in your skin for life. The virus can wake up when your immune system is under stress – for example, during a viral illness, hormonal changes or sunburn. It can also flare up when older children have periods.

Herpes simplex virus is very contagious. You can get it through skin-to-skin contact, contact with an infected person’s saliva, or contact with infected objects. It can spread even if people don’t have any blisters.

Children who have weak immune systems because of illness or medicines have an increased risk of frequent, long-lasting or severe cold sores. They also have an increased risk of developing complications. Young babies are also at increased risk of developing complications.

Cold sores are quite common in older children.

Symptoms of cold sores

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

Cold sores generally clear up completely after 7-10 days. They don’t leave any scarring.

Some children get cold sores several times a year, usually in the same place.

The first time children get herpes simplex virus, the cold sores are often mild. In some children, the first infection doesn’t even cause symptoms. In other children, the first infection might cause a lot of cold sores in the mouth, with fever and pain. This is known as herpes simplex mouth infection.

Complications of cold sores

A very rare complication of herpes simplex virus is an infection of the brain known as encephalitis.

Medical help: when to get it for children with cold sores

You should take your child to the GP if your child has:

• cold sores that are weeping or starting to spread
• a fever as well as cold sores
• cold sores that make drinking hard even after pain relief – this might lead to dehydration, especially in younger children
• painful cold sores several times a year or trouble attending school because of cold sores.

See your GP or go to your nearest hospital emergency department if your child a seizure or is confused, drowsy or behaving unusually. This could be a sign of encephalitis.

If you have a baby aged under one month, you should take them to the GP if they’ve been kissed by someone with cold sores or they’ve touched the face of someone with cold sores.

You know your child best. If your child seems unwell, trust your instincts and seek urgent medical attention.

Treatment for cold sores

Cold sores usually don’t need special treatment.

If your child is really uncomfortable, paracetamol or ibuprofen in recommended doses can help ease the pain.

Your GP or pharmacist might recommend povidine-iodine ointments like Betadine or anti-viral ointment like aciclovir. These ointments can help cold sores go away faster if you apply them 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 medicine to reduce how often outbreaks happen and how long they last.

Babies might need to go to hospital to be assessed and get anti-viral medicines.

If your child has cold sores, make sure your child is getting enough to drink, even if drinking is painful. This helps to prevent dehydration. You can give your child oral rehydration solution like Gastrolyte or Hydralyte, which you can get as liquid or ice blocks from any pharmacy.

Don’t give aspirin to children under 12 years unless it’s prescribed by a doctor. Aspirin can make your child susceptible to Reye’s syndrome, a rare but potentially deadly illness. If you’re giving your child any over-the-counter medicines, check with your pharmacist or doctor to make sure these have no aspirin.

Prevention of cold sores

To prevent cold sore sores, your child should avoid:

• direct contact with an infected person’s cold sores
• sharing utensils, glasses or towels with someone who has cold sores
• things that trigger cold sore outbreaks – for example, lack of sleep and sunburn.

If you have a baby, it’s best for people with cold sores to avoid direct contact with your baby. If this isn’t possible, they should wash hands carefully before holding your baby and also avoid kissing your baby.