Cold sores and babies

Unhappy baby

For newborn babies, cold sores can be dangerous. In rare cases, the virus which causes cold sores can even be fatal for babies who are yet to develop the immunity to fight it. You can reduce the risk of your baby developing cold sores by following the steps discussed below.

Cold sores are small spots or blisters, which are usually found around the mouth, caused by the herpes simplex virus (HSV). The same infection causes genital herpes, although usually they're different strands (HSV-1 is most commonly responsible for cold sores, and HSV-2 herpes).

Are cold sores contagious?

Yes, HSV is highly contagious. If someone has a cold sore, the virus is easily passed from them to another person by direct contact with the cold sore. If you touch your baby's cold sore then wash your hands immediately. Use separate cloths, flannels and towels for your baby. Try to prevent your baby from rubbing her eyes.

Why can cold sores be dangerous for babies?

Before six weeks, babies have not developed their immune system and are therefore more susceptible to contracting infections or viruses. Although cold sores are usually mild, if a baby gets the virus it can spread quite rapidly to other areas, often without obvious symptoms, and in some cases this can end up being fatal.

If you have a cold sore, it is important to avoid direct contact with anyone who has a low immunity – including newborns, or people who are undergoing treatments such as chemotherapy which weaken the immune system.

Are there any other risks with cold sores?

For older babies and young children, cold sores can cause a lot of discomfort, especially with drinking, and this can lead to dehydration. Children under five are also more likely to experience further side effects from HSV; including high temperature, headache, swollen gums or sore throat.

Sometimes, HSV can spread to other parts of the body and cause different infections. It can be contracted through other open wounds, including eczema, so be particularly careful of contact in these circumstances.

Are the risks of getting a cold sore heightened during pregnancy or after birth?

Unfortunately, cold sores often manifest themselves when someone is tired, stressed or run-down – something new and expectant mothers will know is common in pregnancy and the early stages of parenthood. For this reason, it's not uncommon for pregnant women and new mothers to get a cold sore.

Woman with cold sore

What if I, or another family member, are prone to getting cold sores?

The virus should not be contractible unless it has developed into a visible cold sore. Just because you occasionally get them does not mean you are at risk of spreading the virus at all times.

If a friend of family member who is visiting the baby has a cold sore, even in its early stages, you are not being unreasonable to ask them to avoid contact with your child – it is better to be safe than sorry.

What if I get a cold sore before or soon after giving birth?

If you get a cold sore for the first time while you are pregnant, especially nearing your due date, you should talk to your doctor about the possibility of passing HSV to the baby. It is rare for the virus to be passed on, if it's in the form of a cold sore; however, if you have genital herpes there is a greater risk of passing the infection, and in some cases doctors will recommend a c-section to eliminate some of the risk.

If you have a newborn, treat your cold sore immediately (as soon as you begin to feel a tingle) and avoid contact between your baby and the cold sore – this means no kissing, or holding them to your face (difficult as that may be). Wash your hands regularly and do not share any items such as towels or cups which come into contact with your mouth.

What should I do if I think my baby has a cold sore, or if they may have come into contact with the virus?

Contact your doctor immediately to get them checked. It may not be threatening, but it's better to be safe than sorry. If you're still in hospital, ask to speak to a specialist who can check for specific reactions. Remember, the virus may not show as a cold sore on the child in its first instance.

Don't feel stupid for asking, it may sound like something silly to worry about but it can (in rare, but nonetheless devastating, circumstances) be fatal – so it's worth voicing any concerns you have.

What Mumsnetters say about cold sores and babies

“If someone turns up at the house with a cold sore, I take them aside and discreetly say: 'Oh you poor thing, you have a cold sore! I get them all the time and it's so important not to kiss the children as you know they are so contagious…' I have learnt never to presume that people will be careful.”

“I would absolutely not go anywhere near a baby if I had a cold sore and, if I saw anyone with a cold sore going to kiss my baby, I would be very angry!”

“Cold sores aren't automatically dangerous in babies, but they can be. When my daughter first caught one, she had a terrible reaction and ended up in hospital, but it took several days for the virus to develop and she had hundreds of sores on her face and in her mouth. If your baby has one cold sore it shouldn't be a big problem. But keep an eye on her temperature and see your GP if you're worried.”

“I have suffered from cold sores all my life. My two daughters have never suffered from them, because I act responsibly when I have an outbreak.”