Canker Sore

Canker sores — or aphthous ulcers — are small, shallow ulcers that occur in the lining of your mouth. A canker sore starts as a white or yellowish mouth sore with a red border. They’re usually very small (less than 1 millimeter) but may grow to 1/2 inch to 1 inch in diameter.

You can get canker sores on your tongue, gums, roof of your mouth, inside of your lip or under your tongue. They can be painful and often make eating and talking uncomfortable.

There are two types of canker sores:

• Simple canker sores: These may appear three or four times a year and last up to a week.
• Complex canker sores: These are less common and occur more often in the people who have previously had them.

Are canker sores an STI?

No. Canker sores aren’t herpes or any other type of sexually transmitted infection (STI). In fact, they’re not contagious at all. So, you can’t spread them through kissing or sexual contact.

Canker sore vs. cold sore: Are they the same thing?

No. Although these sores are often confused for each other, they’re not the same.

Cold sores — sometimes called fever blisters — are caused by herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2). Because cold sores are caused by viruses, they’re highly contagious and can spread through close personal contact, such as kissing or oral sex. Cold sores are fluid-filled blisters, and they can appear in clusters on your mouth or genitals.

Canker sores, on the other hand, aren’t caused by an infection and aren’t contagious.

Who gets canker sores?

Anybody can develop canker sores. But they’re most common in teens and people in their 20s. Women and people assigned female at birth (AFAB) are more likely than men and people assigned male at birth (AMAB) to get canker sores. Experts believe this could be due to hormonal changes.

How common is this condition?

Canker sores are fairly common. Approximately 20% of the U.S. population has had a canker sore at least once in their lifetime.