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Canker sores and oral herpes, also called cold sores, are common conditions with some similarities, which could lead you to confuse the two. Canker sores and cold sores both occur in or around your mouth and can make eating and drinking uncomfortable.

While some people use the terms “canker sore” and “cold sore” interchangeably, these conditions have distinctly different causes, appearance, and symptoms. We will explore the differences between canker sores and cold sores in this article.

Canker sores are ulcers that appear in your mouth, usually on the soft tissue at the sides of your teeth or on the roof of your mouth. They are round and white, with a red border.

Canker sores appear because of a weakness in your immune system or a nutritional deficiency. They are not contagious and usually go away on their own without treatment.

Cold sores, which are sometimes called fever blisters or oral herpes, are caused by the herpes virus. They are small blisters found on or around your lips.

Two strains of herpes can cause a cold sore: HSV1 typically occurs in the mouth, but HSV2, which is usually found on your genitals, can also cause cold sores. Both strains of herpes are very contagious.

Canker sores Cold sores
Not contagious Extremely contagious
Found inside your mouth Found on or around your lips
Are caused by a number of different factors Are caused by the herpes virus
Appear as flat white sores/ulcers Appear as fluid-filled blisters

Canker sores are small ulcers that are found in your mouth. They can be triggered by a host of different factors, including:

  • bacteria
  • a weakened immune system
  • stress
  • hormonal shifts
  • dental work

People with celiac disease, HIV, and Crohn’s disease may have a higher risk of developing canker sores. They are more common in women, and may even run in families.

Small, single canker sores are painful, but they are not usually a cause for concern. They typically clear up within a week or two. Canker sores that occur in clusters, or are larger and deeper than normal, can take additional time to heal.

Cold sores are raised blisters found on and around your lips. They are caused by the herpes virus, which is spread from person to person. The virus is transmitted through close contact, like kissing.

According to the Mayo Clinic, about 90 percent of people worldwide test positive for the virus that causes cold sores.

The HSV1 and HSV2 virus strains are contagious even when sores aren’t visible. But when fever blisters are present, the virus spreads more easily.

After you’ve had one cold sore, future cold sore outbreaks can occur. Stress, hormonal shifts, and climate exposure can all trigger fever blisters.

Cold sores and canker sores are treated differently.

Canker sore treatments

There are several at-home remedies that can speed the healing of canker sores. None of these treatments will get rid of a canker sore instantly, but they may relieve symptoms and speed up the healing process. These treatments include:

Over-the-counter products for treating canker sores include benzocaine and hydrogen peroxide rinses. If you have a canker sore that won’t go away, your doctor may prescribe a corticosteroid ointment or an antibiotic.

Cold sore treatments

Oral herpes usually clears up within seven to 10 days. While you wait for the outbreak to clear, you can try home remedies to soothe symptoms and speed up healing. Home remedies for oral herpes include:

  • ice packs to reduce inflammation
  • Ibuprofen to reduce pain and inflammation
  • aloe vera to soothe cracked and inflamed skin

If home remedies aren’t working, or if your outbreaks are continuous, your doctor may prescribe acyclovir (Zovirax) or valacyclovir (Valtrex) to treat and prevent future outbreaks.

To prevent canker sores, practice good oral hygiene. See if you can identify what triggers your outbreaks, and make sure you’re getting a balanced diet. Stress coping techniques may also help you to get fewer canker sores.

If you are getting canker sores often, speak to your doctor about possible causes and specific prevention techniques.

Once you have had one cold sore outbreak, it’s always possible that you will get another one. The best way to prevent a cold sore is to treat the outbreak as soon as you feel the sore coming but before it appears on your skin.

Avoid intimate contact, including kissing, with anyone who has a visible cold sore. Replacing toothbrushes and cosmetics that have touched your mouth while you had a cold sore can help prevent reinfection.

Canker sores and cold sores are both painful conditions that can cause difficulty when you eat and drink. But they are not the same thing.

While a virus causes cold sores, the causes of canker sores are less straightforward. If either kind of sore is not healing, talk with your doctor about possible prescription treatments.