What to Know About Cold Sores in Children

Medically Reviewed by Renee A. Alli, MD on April 22, 2023
Written by WebMD Editorial Contributors
4 min read

Cold sores are common infections in children. They’re also called fever blisters, oral herpes, or herpes labialis. Despite their name, cold sores don’t have anything to do with colds. Cold sores are very infectious. For most children, they will go away on their own but some children can get very sick from them. 

Cold sores are small blisters that appear around the lips and mouth. They can sometimes appear on the nose, chin, and cheeks. The blisters become fluid-filled sores and a crust forms. 

Symptoms can appear differently in each child, depending on whether this is their first time having cold sores or if they've had them multiple times. When your child has a cold sore for the first time, they may also have:

  • Fever
  • Swollen lymph glands
  • Sore throat
  • Excessive drooling
  • Irritability and restlessness
  • Swollen and red gums that may bleed.

There is no cure for cold sores. They can be prevented, and the pain and discomfort can be eased. 

Cold sores are caused by the herpes simplex virus type 1 (HSV-1). There are two types of HSV. Type 1 is what causes cold sores. Type 2 (HSV-2) is sexually transmitted and causes genital herpes.

Cold sores are very contagious. They can spread through saliva, and they can infect others by kissing and sharing items like cups, utensils, towels, or toys. The virus can also spread through skin contact. Some people with the virus may not have any symptoms but can still spread it through their saliva. 

A study in 2018 found that almost half (47.8%) of Americans between the ages of 14 and 49 have the HSV-1 virus. 

Once your child has been infected with the cold sore virus, they will carry it with them for the rest of their lives. The virus will be inactive or dormant in nerve cells until something triggers an outbreak. It then travels to the lips, where cold sores break out.

Some common cold sore triggers include:

  • Illness, like the flu
  • Stress 
  • Fatigue
  • Cracked or damaged lips
  • Dehydration
  • Poor diet
  • Changing hormones such as during a menstrual period
  • Exposure to extreme hot or cold temperatures.

Your child’s doctor can usually diagnose the condition by looking at the sores. They may also do skin scraping to examine it for the virus. A blood test may also be done.  

Cold sores can be unpleasant to look at and may hurt. But most cases aren’t serious. The sores usually go away after a few days. You may want to take your child to a doctor in a few situations.

If your baby is under 6 months of age. Young babies’ immune systems aren’t fully developed. Cold sores could cause your baby to develop serious health problems such as high fever and seizures.

If this is their first cold sore. See your pediatrician for your child’s first cold sore infection especially if your child has a weakened immune system or a chronic skin condition like eczema (atopic dermatitis). Children with eczema are more likely to get skin infections in general. 

The cold sore virus can cause a rare but painful infection known as eczema herpeticum. Symptoms include fever, swollen lymph nodes, and clusters of itchy and painful blisters, usually on the face and neck. Eczema herpeticum can be severe and infect various organs including the brain, lungs, and liver. 

If your child has sores near their eyes. The virus can spread to the eye and cause a potentially serious cornea infection called HSV keratitis. The cornea is the transparent dome at the front of your eye. Severe infections can lead to blindness. 

If the sores don’t heal by themselves within two weeks. You might want to check with your doctor in case your child has any other medical conditions. 

If your child frequently gets cold sores. Your child’s doctor may prescribe some antiviral medication if your child gets more than five or six cold sore outbreaks a year.

If your child gets a headache, fever, drowsiness, or confusion. This may be a sign of a rare disorder known as herpes simplex encephalitis. Encephalitis is when the brain becomes inflamed and swollen. There are about 2,000 cases of herpes simplex encephalitis in the U.S. each year.

Avoid acidic foods. Acidic foods such as citrus fruits and tomatoes can irritate a cold sore.

Cold compresses. Apply a cold wet cloth to the sore. This will help reduce redness and pain.

Moisturize. Keep your child’s lip and mouth area well moisturized. This will prevent the sore from drying out. Once the sore has healed, throw away the lip balm.

Pain relief. If your child won’t eat or drink because of the pain, talk to their doctor about giving them acetaminophen or ibuprofen.

  • Practice good hygiene such as regular and thorough hand washing.
  • Make sure your child doesn’t touch the cold sore. 
  • Disinfect things that are touched often, such as toys and doorknobs.
  • Don’t share utensils, cups, towels, or lip balms with anyone with a cold sore. 
  • Don’t allow your children to share toys, especially if they put toys in their mouths.