Canker sore or cold sore: How to tell the difference


Canker sore or cold sore: How to tell the difference

If you develop a sore in or around your mouth, you might wonder whether it’s a canker sore or cold sore.
Although it can be easy to confuse the two, they are quite different from each other.
“Although people sometimes mistake one for the other, canker sores and cold sores are very different conditions both in terms of what causes them and how they are treated,” says Tidelands Health family medicine physician Dr. James Turek, who practices at Tidelands Health Family Medicine at Garden City. “However, they do share one similarity – they can both be painful and disruptive to our day-to-day lives.”
A canker sore is a small ulcer or group of ulcers that develop in the mouth. A cold sore, also known as a fever blister, is a fluid-filled blister or cluster of blisters that occurs near the lips, gums, tongue or on the roof of the mouth.

The cause of cold sores

A cold sore is caused by the herpes simplex virus type 1, a contagious virus.
“Herpes simplex virus type 1 is usually transmitted through contact with an infected person, such as through sharing food utensils” says Dr. Turek. “However, it’s not typically transmitted sexually like herpes simplex virus 2, the other form of the herpes simplex virus.”
A lot of Americans — an estimated 50 percent of the population — have been infected with herpes simplex virus type 1, and between 20 to 40 percent of infected people develop cold sores as a result.
“The virus can remain dormant for long periods of time without any symptoms being present, then one day you can develop a cold sore unexpectedly,” Dr. Turek says.
Cold sore outbreaks are thought to be caused by a variety of factors, including stress, illness, fever, menstruation, sunlight, a weakened immune system, a lack of sleep and more.

The cause of canker sores

Unlike cold sores, there is no known cause for canker sores. But the small, round ulcers also are a widespread problem (it’s estimated that about half of Americans have had them).
They appear on the inside of the lip or cheek, under the tongue or in the back of the throat. Unlike cold sores, canker sores don’t occur outside of the mouth.
“They usually have red edges and are white, gray or yellow at the center,” Dr. Turek says.

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Canker sores are linked to a variety of triggers including food allergies, stress, hormonal changes, infections, vitamin deficiencies and spicy foods. They can can also be caused by trauma to the mouth, such as when you accidentally bite the inside of your cheek.
In addition, some medical conditions including Crohn’s disease, ulcerative colitis and HIV/AIDS can cause canker sores.
Unlike a cold sore, a canker sore is not contagious.
“They aren’t spread through saliva or by contact with another person,” Dr. Turek say. “Sometimes one develops, and you simply won’t know why.”

Canker sore prevention and treatment

To keep canker sores at bay, Dr. Turek suggests regularly brushing and flossing after meals, watching what you eat and reducing your stress levels. If you wear braces or use other dental equipment that can irritate your mouth, consider speaking with your dentist or orthodontist about ways to eliminate any sharp surfaces that may exist.
While canker sores typically go away on their own within two weeks, there are times when the condition may warrant a visit to a physician.

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“If a canker sore is very large or persistent (lasting two weeks or more), prevents you from eating or drinking or presents with a fever, it’s a good idea to seek help from a primary care physician or another qualified provider,” says Dr. Turek. “In some rare cases, a canker sore can be a sign of another problem, especially among older people who are experiencing them for the first time.”
There are a variety of over-the-counter and prescription medications that can help treat canker sores. Gargling with mouthwash or salt water, while painful at first, may help reduce pain.

Cold sore treatment

Like canker sores, cold sores will usually disappear on their own within two weeks. Although there’s no cure or vaccine for herpes simplex virus 1, the virus that causes cold sores, prescription and over-the-counter antiviral medications can help reduce pain and hasten healing.
Patients with frequent outbreaks can also talk with a physician or other qualified care provider about using a daily antiviral medication to reduce the risk of reoccurrences.

Other ways to treat cold sores:

  • Use a cold compress to help reduce pain and redness.
  • Apply petroleum jelly, which can help limit cracking.
  • Use ibuprofen or acetaminophen to ease the pain.

Although cold sores are usually not a serious condition, herpes simplex virus 1 is highly contagious so people should try to prevent its transmission to others. The virus is most contagious when a lesion is visible and oozing, and It can easily be spread through close contact such as kissing, sharing utensils, drinking glasses and cosmetics.
“Keep in mind that you can still spread the herpes virus through close contact even after the cold sore disappears,” Dr. Turek says. “As a result, it’s wise to avoid eating or drinking or sharing food and drink with other people.”

When you have a cold sore:

  • Don’t touch, pick or scratch the lesion.
  • Don’t pop it, which can increase the risk of spreading it to another person or causing another lesion
  • Avoid eating or drinking acidic foods or hot and spicy foods, which can add to the discomfort.
  • Avoid foods that contain amino acids such as seeds, almonds, chocolate and peanut butter, which the virus needs to thrive.
  • Wash your hands frequently.
  • Drink plenty of water to avoid dehydration.
  • Be especially careful around babies, pregnant women or people with weakened or compromised immune systems.

If you suffer from frequent cold sores, are struggling with one that won’t heal, develop a high fever or have a lesion that seems to be spreading, make an appointment with your physician or other qualified care provider.

Dr. James Turek is a family medicine physician who practices at Tidelands Health Family Medicine at Garden City. 

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