Canker Sores vs Cold Sores

What’s the difference and what to do if you have one

By Dr. Stephanie Vera, DDS

Despite often being confused for one another due to similar sounding names, canker sores and cold sores are two very different things. One is a highly contagious virus, and the other is a benign, although painful, ulcer. You may find yourself wondering, “How do I know if I have a canker sore or a cold sore?” Don’t worry, I’m here to help you tell the difference and give you tips on how to prevent them, how to treat them, and when you should see your dentist.

Canker Sores

Canker sores, also known as apthous ulcers, occur inside the mouth - usually on your gums or cheeks. They are round or oval shaped with a white or yellow center and red border. While they’re not contagious, they can be very painful – luckily, they generally go away on their own within a week or two. While there is no definitive cause of canker sores, they have been linked to food allergies, SLS allergies, trauma to the tissue, vitamin B, folic acid, and zinc deficiency, and autoimmune diseases like Celiac’s, Cohn’s, and Hashimoto’s disease.

Finding the Cause of Your Canker Sores

One of the best ways to get relief from canker sores is to prevent them – or at least reduce their frequency. The most important thing you can do for a canker sore is to try and find out what the cause is. You can try an elimination diet and avoid certain foods like wheat/gluten, spicy foods, or acidic foods like tomatoes and citrus. It is also strongly recommended to switch to an SLS-free toothpaste. And since recurrent ulcers have been linked to certain vitamin deficiencies, starting on a multivitamin with high amounts of B vitamins, folic acid, and zinc can help as well.

How to Treat Canker Sores

Generally, canker sores heal on their own without any intervention, but when they cause a lot of pain or discomfort patients – my husband included – often look for ways to speed up recovery. The two things I recommend are:

1.  Taking a Lysine supplement every day at the first sign of a “hot spot” until the ulcer has fully healed.

2. Rinsing with a super saturated saltwater rinse three times a day when the ulcer appears. This will increase blood flow to the ulcer, reduce inflammation, and speed up healing time.

At times when the pain is too intense, or your canker sore is in an area that causes a lot of discomfort, you can see your dentist for Debacterol or laser treatment in office. Debacterol is a prescription-only topical liquid applied directly to the canker sore and then rinsed, while a low light laser is used over the ulcer. Both options will provide immediate pain relief and help new cells to start growing around the canker sore.

Cold Sores

Cold sores are fluid-filled blisters that show up on or around your lips, usually in the same place. They often start with a burning or tingling sensation followed by a blister and then a scab. Like canker sores, they can be painful and last up to two weeks. Cold sores are reoccurring and caused by the herpes simplex virus. Unfortunately, they are highly contagious when in the blisters burst but can still be passed until they’re completely healed.

What Can Trigger a Cold Sore

Most people who have herpes simplex virus caught the virus in childhood. Once you have been exposed to the virus that causes cold sores, it never goes away. The virus will become dormant but will periodically reactivate. Cold sores can be triggered by:

• Sun and wind exposure

• Hormonal changes

• Stress and fatigue

• Viral infections like the flu or a cold

How to Treat Cold Sores

Cold sores will heal on their own in about 2 weeks, but any dentist can prescribe an antiviral cream or oral medication to help with healing time as soon as you start to feel the itching or burning sensation. The most common prescriptions are Denavir (cream) and Valacylovir (oral medication).

When it comes to cold sores, prevention can help minimize the number of outbreaks you experience. Using a UV chapstick and reducing stress can stop the virus from reactivating. It is also important to avoid spreading the virus to others – never kiss children on the lips and avoid sharing cups or utensils. When your blisters are in the oozing stage, avoid all contact with others, as this is when the virus is most contagious. Frequent hand washing can prevent the virus from spreading person to person or to other parts of the body.

While canker sores and cold sores may not be completely avoidable, remember to take care of your mouth and avoid triggers that may cause them to appear. And if you do happen to get one, don’t worry – there are plenty of ways to help them heal and get you feeling like yourself again!

Dr. Stephanie Vera is a general dentist practicing in Murphy, Texas. She is a graduate of Baylor College of Dentistry and believes education and prevention are essential to a happy, healthy smile.