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Can my baby catch a cold sore?

While cold sores are relatively harmless in toddlers and older children, they can be dangerous in infants under the age of one. Here’s what you need to know to protect your baby.

Can my baby catch a cold sore?

Photo: iStockphoto

Babies are made for snuggles and kisses. But if you or a family member or caregiver has an active cold sore—or even a history of cold sores—you’d be wise to use caution when it comes to kissing and caring for a baby under the age of 12 months. Serious complications, while rare, can develop if a baby contracts the cold sore virus. Here’s what you need to know.

What is a cold sore?

Also known as a fever blister or oral herpes, a cold sore is caused by a highly contagious virus called herpes simplex virus type 1 (HSV-1). (Genital herpes is caused by a different strain called herpes simplex virus type 2, or HSV-2.) It starts as a small blister around the lips or mouth but can sometimes appear on the nose, cheeks or chin as well. After a few days, the blister begins to ooze, then scabs over. It’s a very common virus—according to the American Academy of Pediatrics, more than half the population is infected with HSV by the time they hit adulthood (although they may not actually ever show symptoms), and most exposure happens between ages one and five. Once you’re infected with the virus, it stays in your body for life.

How do you get a cold sore?

The virus spreads through saliva or skin-to-skin contact or by touching an object that was handled by someone infected with the virus. “If you have a cold sore, don’t kiss the baby because it can definitely be transmitted to their skin,” says Roxanne MacKnight, a family physician in Miramichi, NB. She adds that the virus can be transmitted through contact with objects as well, so avoid sharing cutlery, towels or washcloths if you have an active cold sore and wash your hands well before touching the baby and their toys and belongings. Nuzzling the baby or kissing a different part of their body, like their hands, should also be avoided because of accidental contact.

“You can potentially pass along a cold sore through breastfeeding if you touch your cold sore and then your nipple and then the baby nurses,” says Simone Rosenberg, a midwife in Toronto. “We recommend that you wash your hands well and often. It’s important to do everything you can to avoid making contact between the baby and the cold sore.” She adds that midwives typically ask their clients early on in pregnancy if they or their partners have a history of cold sores so that they can talk about best practices before their babies are born.

What if you have an aunt with a cold sore who says that kissing a toddler on top of the head is OK? “You have to come in contact with a mucous membrane, like the eyes or mouth, or an open cut to be infected,” says Jamie Morgan, a physician who specializes in maternal-fetal medicine in Dallas, Texas, and an assistant professor of obstetrics and gynaecology at UT Southwestern Medical Center. “But if there is an active cold sore, try to avoid close contact with the face.” If a parent of a toddler has a cold sore, a doctor isn’t going to tell them to avoid kissing their toddler at all, she adds, but if it’s relatives or friends with active cold sores, asking them to skip any kisses and face nuzzles entirely until a week after the cold sore is gone is probably the best course of action.

When is a cold sore contagious?

An active cold sore—when it is weeping or crusted over—is most contagious. “If you’re starting to feel the signs and symptoms of a cold sore, like tingling and burning, you can be contagious at that stage, too,” says MacKnight. Some medical experts say to err on the side of caution and not allow anyone who has had a cold sore in the previous week to kiss your baby.


If you have a history of cold sores but not an active cold sore or one within the last week, you’re not contagious and it’s OK to kiss and care for a baby or toddler, says Morgan.

Why are cold sores potentially serious for babies?

“Usually, cold sores are fairly benign,” says MacKnight. “You don’t see a lot of complications in young children.” However, babies, particularly those less than 12 months, have immature immune systems. “With young babies, the virus can disseminate, or move quickly, to other areas of their bodies, which means a risk of meningitis,” she says. “It’s rare, but it is a risk.” Viral meningitis (inflammation of the tissue that covers the spinal cord and brain) and viral encephalitis (inflammation of the brain)—a related condition—can cause brain damage or be life-threatening.

At any age, a cold sore can also spread to the eye and cause a potentially dangerous infection called HSV keratitis, she says. This is an infection of the cornea, so it’s very important not to touch a cold sore and then rub your eye. HSV keratitis often heals without damaging the eye, but a severe or untreated infection can cause scarring of the cornea or even blindness.

What are the symptoms of a cold sore in babies?

Signs of HSV-1 infection can be tricky because they are vague and may include lethargy, irritability, fever and poor appetite. Infants may or may not have actual sores, have sores that appear on other parts of their bodies (not just their mouths) or have blister-like rashes on their bodies. It’s a good idea to call your healthcare provider to get it checked out and ask specifically if it could be a cold sore.

Two rare yet serious complications related to HSV-1 infection are meningitis and encephalitis. Symptoms of meningitis in babies include a fever, irritability, a lack of energy, poor appetite, sleepiness or difficulty waking from sleep. (Young children may have similar symptoms, along with headaches, stiff necks or sensitivity to bright lights.) Symptoms of encephalitis in infants and young children include nausea and vomiting, bulging in the soft spot (fontanelle) of the skull, body stiffness, irritability and poor appetite. If your child has any of these symptoms, go to the emergency room.


Because kids older than one have more robust immune systems, the symptoms of a first cold sore are annoying but almost always minor. Blisters may form on the mouth or gums, not just the lips. Your child may also have swollen or tender lymph glands, a sore throat, a mild fever and drooling.

What is the treatment for cold sores?

While complications from HSV-1 in infants are rare, they can be very serious. A baby that has been exposed to the HSV-1 virus and shows symptoms should be seen immediately by a healthcare professional. A blood test can show exposure by detecting particular antibodies that fight the virus. Treatment may include hospitalization to receive IV antiviral medication.

For kids older than a year, your healthcare provider may suggest an age-appropriate dose of children’s ibuprofen or acetaminophen and cold cloths to help soothe any itchiness or pain. Avoid potentially irritating acidic foods, such as oranges and tomato sauce. If the sore is swollen, red or hot to the touch, it could be infected and needs to be seen by a healthcare professional. Try to encourage your child not to pick at their sores and to wash their hands often. Wash their toys frequently with soap and hot water.

The bottom line? Cold sores are for life. While they’re mainly a nuisance in toddlerhood and beyond, they can be very serious for babies, so take the right precautions and don’t be shy about insisting that family members and caregivers do the same.


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