Baby Symptoms & Conditions

Mouth Sores In Babies

What the heck are those weird sores on baby’s mouth? Here’s how to tell — and what to do about them.

What are mouth sores in babies?

Occasionally, but not often, your baby may develop red or purple sores or a cluster of sores along his lips. Or he may have small, open (and sometimes painful) sores inside his lips, cheek, gums or tongue.

What could be causing my baby’s mouth sores?

Sores on the outer edge of the lips that are red or purple can be caused by the herpes simplex virus and can be passed onto baby through something as innocent as an infected relative’s gentle kiss. Sores inside the mouth, on the other hand, are considered canker sores, which can also be caused by a virus, stress or a trauma (like biting himself).

When should I take my baby to the doctor with mouth sores?

Typically mouth sores will go away on their own, but if a sore lasts more than a couple of weeks, or if he develops a fever or other symptoms like a rash or swollen lymph nodes, call your doctor.

What should I do to treat my baby’s mouth sores?

A pain reliever like acetaminophen can help reduce the inflammation, and you can try using an over-the-counter oral gel to provide some surface relief.

By Wendy Sue Swanson, MD, FAAP, pediatrician with Seattle Children's Hospital, Everett Clinic