Overview

Both fever blisters and canker sores are common across all ages and can be painful. However, they are separate conditions with different causes. Read further to learn how to tell them apart and find out which treatments might help ease the pain.

Fever Blisters (also known as cold sores) are painful fluid-filled sores that form on the outside of the mouth around the lips. Fever blisters are very contagious.

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Ectodermal dysplasias (ED) are disorders that affect the skin, sweat glands, hair, teeth, and nails. Some individuals with ED may also have cleft lip and/or palate. ED can additionally cause problems with the immune system as well as hearing and vision.

More than 180 specific types of this condition have been identified.

Ectodermal dysplasias occur when the outer layer of tissue (ectoderm) of the embryo does not develop normally. If two or more body structures derived from the ectoderm are affected, a person is considered to have ED.

ED is a rare disease, defined in the U.S. as a condition that affects fewer than 200,000 people.