Cold Sores in Babies and Newborns: Signs, Risks and What to Do
A cold sore in a baby is not something to treat at home. Cold sores are caused by the herpes simplex virus, and in newborns, especially in the first six weeks of life, the virus can spread through the body and affect the brain and organs. Neonatal herpes is rare, affecting about 10 in every 100,000 births, but it can be life threatening, so any blister, sore or unexplained fever in a young baby needs a doctor the same day. Most babies catch it during birth, and about 1 in 10 catch it after birth, often from a kiss. That’s why the best natural care for your baby is prevention: no kisses from anyone with a cold sore, clean hands, and less close contact with other people in the first two months. Older babies and toddlers can get a first herpes infection in the mouth, with fever and sores all over the gums, which also needs a doctor. For cold sores in adults, see our complete guide to cold sores and our guide to herpes on lips.
The short version
- Baby under 3 months with a blister, sore or fever: see a doctor the same day, or go to the emergency room.
- No home remedies on babies. This is one situation where you follow standard medical care.
- Prevention is the natural care: nobody with a cold sore kisses the baby, everyone washes their hands, and keep close contact limited in the first two months.
- If you have a cold sore: don’t kiss your baby, cover the sore, wash your hands and keep breastfeeding unless there’s a sore on your breast.
- Toddler with fever and sores all over the mouth: likely a first herpes infection. See your GP and keep them drinking.
Why Home Remedies Aren’t Worth the Risk for Babies
I’m a big believer in natural care, and I’m personally very cautious about giving medication to babies. But when it comes to herpes in an infant or toddler, it’s simply not worth the risk to try home remedies first. A big part of natural care is prevention, and that includes protecting your child from infections that can be dangerous, and herpes is one of them.
If your baby does get herpes, this is exactly the kind of emergency modern medicine was built for. Newborn herpes is treated in hospital with medicine given straight away, and doctors say the treatment should be tailored to the baby’s symptoms and test results. There’s no question here: follow standard medical care. Early treatment makes a real difference.
Are Cold Sores Dangerous for Babies?
For newborns, yes. A baby’s immune system is still very new, and in the first weeks it can’t stop the herpes virus the way an older child or adult can. Neonatal herpes can stay limited to the skin, eyes and mouth, or spread to the brain or through the whole body. The more it spreads, the more serious it is.
What makes it tricky is that the typical blisters don’t always appear. In a large study of babies with neonatal herpes, 39% of babies with widespread infection and 32% with brain infection never had skin blisters. So a young baby who is unusually sleepy, feeds poorly or has a fever needs a doctor, even without a sore.
Until what age are cold sores dangerous?
The first six weeks are the most dangerous time, and the risk stays higher in the first three months. After that, a baby’s immune system is better able to handle the virus, though a first infection can still make an older baby or toddler quite ill. I recommend keeping extra care around close contact for the first two months, while your baby is still getting to know the germs of this world.
How Do Babies Get Herpes?
- During birth. This is how most babies catch it, about 85% of cases. The risk is highest when a mother catches genital herpes for the first time late in pregnancy.
- After birth. About 10% of cases, usually from a kiss by someone with a cold sore, or from hands that touched a sore.
- Before birth. Rare, about 5% of cases.
Can a baby get a cold sore from a kiss?
Yes. Kissing is the most common way a baby catches herpes after birth, and it doesn’t have to be on the lips. A kiss on the cheek, forehead or hands can pass the virus on, and herpes can be on someone’s lips even when they have no visible sore. There’s a very good reason many mothers don’t want strangers, or even people close to them, kissing their baby. You’re allowed to say no.
Can a baby get herpes from the mother?
Yes, but the timing matters a lot. A study of pregnant women found that when a mother’s herpes infection was already settled by the time of birth, it didn’t increase the risk for the baby. But when the mother caught genital herpes shortly before labour, 4 of 9 babies got neonatal herpes. That’s because a mother who has had herpes for a while passes protective antibodies to her baby through the placenta. If you have herpes, or your partner does, tell your midwife or obstetrician during pregnancy so they can plan a safe birth.
What Does a Cold Sore Look Like on a Baby?
On a baby, herpes can look like:
- A small cluster of blisters on the lip, face, scalp or body
- Blisters or a red, weepy eye
- Sores inside the mouth
- A new rash that doesn’t look like normal baby spots
Other signs that matter just as much, especially in the first six weeks: fever or a low temperature, unusual sleepiness, floppiness, poor feeding, irritability or seizures.
It’s easy to confuse early herpes with baby acne, milk spots, drool rash or impetigo. Don’t wait to see what it becomes. If your baby is under three months, a doctor should look at any blister.
A Toddler’s First Herpes Infection: Sores All Over the Mouth
Older babies and toddlers often catch herpes for the first time from a family member, at nursery or through shared toys and cups. The first infection usually doesn’t look like a cold sore. It shows up as primary herpetic gingivostomatitis: swollen, sore gums and many ulcers inside the mouth. In a study of 185 children admitted with it, almost all had a fever, 84% had mouth ulcers and 68% had swollen or bleeding gums, and the fever lasted about five days on average.
The biggest risk is that your child stops drinking because it hurts. See your GP or paediatrician, and at home:
- Offer small sips often: cool water, milk, diluted juice without citrus, or ice lollies.
- Give soft, cool foods like yogurt, porridge and mashed vegetables.
- Use pain relief suitable for your child’s age, as advised by your pharmacist or doctor.
- Watch for signs of dehydration: fewer wet nappies, a dry mouth, no tears, unusual sleepiness.
- Keep their cups, cutlery and towels separate, and wash hands often.
Not sure if it’s herpes or something else? A single white sore inside the mouth is more likely a canker sore. Here’s how to tell a cold sore or a canker sore apart, and read more about herpes on the face and tongue.
What to Do by Age
| Age | What to do |
|---|---|
| Newborn to 6 weeks | Any blister, sore, fever, sleepiness or poor feeding: go to the emergency room straight away. |
| 6 weeks to 3 months | See a doctor the same day for any blister or sore, and urgently if there’s a fever. |
| 3 months to 1 year | See your GP or paediatrician to confirm it. Go urgently if near the eye, if baby won’t drink or seems unwell. |
| Toddler | See your GP for a first infection or sores in the mouth. Focus on fluids, comfort and hygiene. |
You Have a Cold Sore and a Newborn: How to Keep Your Baby Safe
If you get cold sores, you can still care for your baby safely. These are the rules I’d follow:
- Don’t kiss your baby anywhere while you have a cold sore, from the first tingle until the skin has fully healed.
- Cover the sore at all times. Use your ointment and a cold sore patch throughout the outbreak, so the sore isn’t exposed.
- Wash your hands before touching your baby, and never touch the sore and then your baby.
- Don’t share cups, spoons, towels or face cloths with your baby.
- Tell your midwife, health visitor or doctor that you have an outbreak.
For mum or dad’s cold sore, never for the baby
The Aromafisis beeswax ointment with oregano is what we use at the first tingle. Put it on your own cold sore, cover it with a patch, and wash your hands before you touch your baby.
Not an affiliate link. For adults only. Never apply ointments, oils or creams to a baby’s skin without a doctor’s advice.
For more on shortening your own outbreak, see how long a herpes outbreak lasts, cold sore remedies over the counter and how to sleep during a herpes outbreak, which covers covering a cold sore at night.
Breastfeeding with a cold sore
Breastfeeding is one of the most important ways to support your baby’s health, and you can keep breastfeeding with a cold sore or with herpes. Just don’t kiss your baby, and keep the sore covered. The one exception is a herpes sore on your breast or nipple: then don’t feed from that side, because babies have caught serious herpes infections from sores on the breast. Feed from the other breast and speak to your midwife or doctor.
Breast milk supports your baby’s immune system in many ways. For herpes specifically, though, most of the protection comes earlier: a mother who has had herpes for a while passes antibodies to her baby through the placenta during pregnancy. Breast milk itself carries only small amounts of herpes antibodies, so it’s a wonderful support, but not a replacement for the prevention rules above.
When cold sores keep coming back after birth
Many mothers notice more cold sores in the months after giving birth. Little sleep, a body that’s recovering and the pressure of caring for a newborn all weaken the immune system, and stress is one of the strongest herpes triggers. If your outbreaks keep returning, it may help to talk to a psychologist or counsellor. The stress of being a new mother might be expressing itself this way, and looking after yourself is also looking after your baby. We explain the main triggers in how to avoid a herpes outbreak.
Protecting Your Baby in the First Two Months
- Ask visitors not to kiss the baby, especially on the face and hands. This includes family.
- Anyone with a cold sore stays away from the baby until it has healed, or at least keeps it covered and doesn’t hold the baby close to their face.
- Hands first: everyone washes their hands before holding the baby.
- Keep close contact limited to the people who care for your baby every day.
- Siblings with a cold sore shouldn’t kiss or share toys with the baby. Explain it kindly and keep an eye on it.
Vaccinations During a Herpes Infection
If your baby is ill or being treated for herpes, the regular vaccination schedule won’t automatically adjust for that. As a holistic mom, I think it’s important to ask about it yourself, so your child’s body can focus on getting better. Talk to your paediatrician about whether any vaccinations due during or just after the illness should wait until your baby has recovered. Doctors routinely delay vaccines during a moderate or serious illness, so this is a normal question to ask, and every child is different. Make that decision together with your doctor rather than skipping or cancelling vaccines on your own.
Cold Sores During Pregnancy
A cold sore on your lip during pregnancy is very unlikely to harm your baby, especially if you’ve had cold sores before, because your body has already made antibodies. The concern is genital herpes caught for the first time late in pregnancy, which carries the highest risk for the baby. Tell your midwife or obstetrician if you or your partner have ever had herpes, and avoid oral and genital sex with a partner who has an outbreak, especially in the last three months. For more on herpes in general, see genital herpes outbreak treatment at home and herpes outbreak symptoms.
When to Get Help
- Go to the emergency room straight away if a baby under three months has a blister or sore, a fever or low temperature, is very sleepy, floppy, feeding poorly or has a seizure.
- See an eye doctor or go to the emergency room the same day for any blister near a baby’s eye, or a red, weepy eye.
- See your GP or paediatrician the same day for a toddler with fever and sores in the mouth, or any child who won’t drink.
- Tell your midwife or obstetrician about any herpes in you or your partner during pregnancy.
Knowing exactly what you’re dealing with is what lets you care for your family the right way. For all our guides on natural herpes care for adults, see natural herpes remedies.
Frequently Asked Questions
Are cold sores dangerous for newborns?
Yes. In the first six weeks, the herpes virus can spread through a baby’s body and affect the brain and organs. Any blister, sore or fever in a young baby needs a doctor the same day.
Can I kiss my baby if I have a cold sore?
No. Don’t kiss your baby anywhere while you have a cold sore, from the first tingle until the skin has fully healed. Keep the sore covered and wash your hands before touching your baby.
Can I breastfeed with a cold sore?
Yes. Keep breastfeeding, don’t kiss the baby and keep the sore covered. Only if there’s a herpes sore on your breast should you avoid feeding from that side and speak to your midwife or doctor.
What does a cold sore look like on a baby?
Usually a small cluster of blisters on the lip, face, scalp or body, or sores in the mouth or a weepy eye. But many babies with serious herpes infections never get blisters, so fever, sleepiness and poor feeding matter just as much.
Can I use home remedies on my baby’s cold sore?
No. Herpes in babies and toddlers should always be checked by a doctor, and nothing should be applied to a baby’s skin without medical advice. For toddlers, comfort care like fluids and soft, cool foods helps alongside the doctor’s advice.
How long should I keep people from kissing my baby?
The first six weeks are the most dangerous, and extra care is sensible for the first two to three months. Anyone with a cold sore should never kiss a baby, at any age.
This article is for general information and does not replace medical advice. If you’re worried about your baby, contact your doctor, call your local emergency number or go to the emergency room.
