The Difference Between Cold Sores & Canker Sores

Differences In Appearance

There are several differences in appearance between a cold sore and canker sore. In fact, a doctor can typically diagnose them on sight based on appearance and location. A canker sore will begin as a tiny bump inside the mouth but burst open one or two days later, leaving a yellowish or whitish open sore with a red border. Many canker sores occur in clusters are 1/8-inch to 1-1/4 inches in diameter. Most canker sores heal completely in ten to fifteen days but recur several times a year. The most common type of canker sore is a minor canker sore, which is very small. Major canker sores are the same except they are more painful and deeper. Herpetiform canker sores, despite the name, are not caused by the herpes virus like cold sores. This form tends to develop later in life as tiny sores in the mouth that occur in clusters of ten to one hundred sores.

Cold sores look very different than canker sores and have different symptoms. These sores often begin with a tingling sensation on the lip or around the mouth followed by the beginning of the sore about two days later. The sore will break open and ooze, leaving a crust over the blister. Cold sores can take up to four weeks to heal and leave an unsightly scab. Cold sores almost always occur outside the mouth, usually on the lip, nose, or near the mouth.

Continue to learn about the differences in treatment for both cold sores and canker sores.