Mouth sores make kids miserable and are quite common. Most are caused by viruses (not strep) and resolve on their own with time.
Here are some specifics on different kinds of mouth sores. First, simple canker sores. These are often one to a few. White bordered and red. They are often in the front of the mouth. They are thought to be caused by a virus. They often recur later on in life. Acidic foods can be avoided until they resolve on their own. Second, is herpangina. It is not herpes – just has a similar name. It is also viral. Ulcers are found on the soft palate and mouth. This can cause enough discomfort that children won’t eat or drink. Cold fluids and ibuprofen or acetominophen can help. Third, hand-foot-and-mouth. Or as I call it hand-foot-mouth-and-butt since lesions are often also found in the diaper area. Lesions can be in the mouth and extensively over the body. This is usually caused by the Coxsakie virus. Again, kids can get miserable enough that they don’t eat or drink. Pushing cold fluids and popsicles can help.
There are no medications to cure these problems. In the past, topical lidocaine was used but it can have serious side effects on the heart and I no longer use it. Magic Mouthwash without lidocaine can be tried and made at home. It is 1:1 Maalox and Benadryl. This can be painted onto lesions with a q-tip and may numb lesions before eating/drinking. Care should be taken that the child doesn’t swallow the mouthwash. Older children can swish it in their mouths and spit.
Lastly, herpes stomatitis. The first time a child acquires a cold sore (herpes) the outbreak can get severe. The lips and oral cavity can be covered in sores. The gums are often inflamed and bleeding. This virus can be treated with acyclovir orally. Some children are afflicted severely enough that they need to be admitted to the hospital for IV fluids and IV acyclovir. Acyclovir works better the earlier you start it so if you suspect this is the case proceed to your doctor. Herpes is a real danger if near the eye and for infants. If your infant has lesions or lesions are near the eye see your doctor or go the ER.
Herpangina Herpes stomatitis