Article at a Glance
- Cold sores are caused by one of the herpes simplex viruses, HSV-1. There's no cure for the virus, and even if you don't have symptoms or an actual cold sore, you can still spread it.
- While rare, HSV-1 infections in newborns can be deadly, causing severe brain damage. This includes transmission during birth through the vaginal canal, or by kissing a newborn baby on the face or sharing a toy or cup.
- You can protect your baby from a cold sore by working with your OB/GYN if you know you have HSV-1 and avoiding a vaginal birth, as well as keeping baby away from adults who have cold sores. While it is more contagious when a person has an active cold sore, remember that the virus can still spread even without one.
Last updated April 21, 2018.
Cold sores are no big deal for adults. They’re uncomfortable and you probably don’t want one on picture day, but they’re not dangerous. However, cold sores aren’t just a minor inconvenience for babies. In fact, they can be extremely dangerous.
This post will go over everything you need to know about cold sores and babies, what to do when you have a cold sore and a newborn, and why you shouldn’t kiss a baby when you have a cold sore.
What are cold sores?
Cold sores, also called fever blisters, are small blisters on and around your lips. They’re caused by one of the herpes simplex viruses: HSV-1. That’s closely related to HSV-2, which causes genital herpes. Cold sores are typically spread by close contact such as kissing, sharing utensils, or sharing a towel with a person who has the virus.
HSV-1 is most contagious while the carrier has actual cold sores, but can also be spread by a carrier with no symptoms. There’s no cure for cold sores — the virus stays in your system forever. Cold sores are also typically untreatable. They’ll go away on their own after a few days or weeks. In certain cases, your doctor may recommend an antiviral medication to speed the healing process.
When an adult catches HSV-1, the first outbreak is often the most severe. It may involve mouth soreness, fever, aches, sore throat, and fever in addition to the blisters around your mouth. Later outbreaks are typically limited to the blisters, without the more severe flu-like symptoms.
HSV-1 can affect the genitals and HSV-2 can affect the face, so it’s important to get tested if you experience any symptoms in either area to determine which form of the virus you have.
How do cold sores affect babies?
Newborn babies’ immune systems are supported by the antibodies they get from their mothers. That means HSV-1 infections are very rare in newborns. When an infection does happen, however, it can be extremely serious.
Mature adult antibodies usually keep the virus isolated around the lips, but babies’ immune systems aren’t strong enough to contain the virus if they do get infected. The virus can spread to rest of the baby’s body, causing permanent and severe damage. It can spread to the baby’s eyes, causing ocular herpes. Left untreated, ocular herpes can cause blindness. It can spread to the baby’s brain, causing brain damage such as meningitis or cerebral palsy.
In severe cases, HPV-1 can be fatal to newborns.
Can babies get cold sores?
As mentioned above, most babies are protected by their mothers’ antibodies. However, that protection sometimes isn’t enough. Babies typically catch cold sores in one of two ways: vertical transmission or horizontal transmission.
Vertical transmission refers to transmission of the virus through the birth canal. This can happen if the mother has a genital herpes infection — remember that both HSV-1 and HSV-2 can affect the genitals. Even when the mother has no outbreak, the virus may be shed from the cells of the birth canal and infect the baby, usually through the eyes or through abrasions caused by forceps. This is the most common form of transmission for newborns.
In some very rare cases, the virus can actually be passed through the placenta to the child during pregnancy. This is called an “intrauterine infection” and can cause spontaneous abortion, growth retardation, scarring, and hydranencephaly. Intrauterine infections typically only occur when the mother is infected with HSV-1 during pregnancy.
Horizontal transmission refers to transmission from another person after birth. This is how most adults catch cold sores. A shared toy, cup, or utensil may be the culprit. A kiss from a relative or friend can also transmit the virus. Remember that you don’t have to have an active cold sore to be contagious.
Finally, HSV-1 may be transmitted through the mother’s breast milk if the mother is infected.
Protecting Your Baby from a Cold Sore
You can protect your child from vertical transmission of HSV-1 by avoiding a vaginal birth. You can work with your doctor to test for the presence of the virus in the birth canal and vagina. If the virus is present, you and your doctor may discuss the possibility of a scheduled C-section to protect your little one from exposure.
To avoid horizontal transmission, the first step is to keep your child away from contact with adults and children with cold sores. The virus is most contagious when there are actual sores. However, those with HSV-1 can be contagious even without sores. That makes prevention harder.
You may choose to discourage people from kissing your child until your little one is a few months old, but many parents find that difficult or impossible to enforce. In any case, you should always keep your child’s toys clean and have everyone wash their hands before picking up your baby to decrease the risk of HSV and other infections.
If either parent has HSV, talk to your doctor about how best to manage the risks and keep your little one safe.
I Kissed My Baby with a Cold Sore. What do I do?
The most obvious symptom of a neonatal HSV-1 infection is the appearance of sores on the mouth, tongue, gums, lips, or throat. If you see sores, you should contact your pediatrician immediately.
However, not all HSV infections will cause sores. The infection can also cause aches, fever, trouble breathing, and swollen lymph nodes. It can also appear in your little one’s eyes as redness, sores, and swelling on the eyes and eyelids. If you see any of those signs, you should seek immediate medical attention to treat the infection before it can cause permanent eye damage.
When you take your little one in for a suspected HSV-1 infection, your doctor may be able to identify it by looking at the sores. The doctor may also order tests to check for infection in your baby’s brain and liver, which may require treatment with antivirals to avoid permanent damage.
The symptoms of an HSV-1 infection are often similar to those of other, less serious infections. It can be tempting to write off minor symptoms as a cold, but remember that it’s always safer to take your child to the doctor when in doubt. HSV-1 infections can become very serious, very fast, and the damage can be permanent.
Legal Issues with Cold Sores and Babies
In some cases, transmission of the HSV virus to your child could have been avoided by appropriate medical care. For example, your doctor may be at fault if she knew that you were infected with an HSV virus and failed to discuss the possibility of a C-section, causing your little one to contract the virus. When a doctor or other health care provider’s negligence leads to your child contracting a serious infection, you may be entitled to compensation for medical expenses, pain and suffering, emotional distress, and other costs associated with your child’s injury.