Is cold sore and canker sore the same

If you've ever had a sore on or near your mouth, you've likely thought to yourself: Is this a canker sore or a cold sore, and what's the difference? Here are three significant differences of a canker sore vs. cold sore to help you determine your next steps for treatment.

Table of Contents Show

1. Appearance
3. Treatments
In this Article
What Is a Canker Sore?
Canker Sore Causes and Risk Factors
Canker Sore vs. Cold Sore
Canker Sore Symptoms
Canker Sore Diagnosis
Canker Sore Treatment
Canker Sore Home Remedies
Canker Sore Prevention
What is the difference between a canker sore and a cold sore?
Are canker and cold sores related?
What causes a canker sore?

1. Appearance

The first way to differentiate a canker sore vs. cold sore is by appearance. As the Mayo Clinic explains, canker sores — also called aphthous ulcers — appear inside the mouth. They develop in soft tissues, such as in the cheeks, gums, under the tongue or on the tongue. Canker sores look like small white or yellow circles surrounded by a red border and may cause discomfort when you eat or drink.

Cold sores, on the other hand, usually appear on or around the lip, as the Mayo Clinic explains. A cold sore often looks like a cluster of blisters, and they can eventually burst, causing oozing and crusting.

2. Causes

Canker sores and cold sores have different underlying causes. According to the American Dental Association, the exact cause of canker sores is unknown. Experts speculate that they may happen as a result of immune issues, mouth trauma, bacteria or viruses.

Cold sores result directly from the herpes simplex virus (HSV-1), according to the Mayo Clinic. This virus is dormant until triggered, which is when you might experience a tingling or burning sensation in your mouth and the development of a sore. Several factors can trigger the recurrence of a cold sore:

Stress
Other viral infections
Fatigue
Exposure to sun or wind
Hormonal changes
Fever

3. Treatments

Both canker sores and cold sores usually heal on their own. Minor canker sores typically take a week or two to heal, according to the Mayo Clinic, while cold sores may take two to four weeks. Cold sores usually do not leave scars; however, major canker sores have the potential to cause scarring.

If your symptoms last longer than you'd like, you can also discuss treatment options with a medical or dental professional. For canker sores, if they are unusually large, clustered or painful, your doctor or dentist may suggest mouthrinses, topical ointments or oral medication.

Because cold sores are caused by HSV-1, the American Academy of Dermatology (AAD) suggests treating them with antiviral topical or oral medications. If you are experiencing discomfort, your doctor or dentist may also prescribe a pain-relief medication. In addition, the AAD strongly encourages the use of sunscreen during an outbreak, as sun exposure can affect the healing of the sore.

Another important note: Unlike canker sores, cold sores are contagious, according to the Mayo Clinic. Therefore, to prevent spreading the virus, you should not share utensils or any other items that touch the mouth.

The easiest way to tell the difference between a canker sore and a cold sore is by its location. If the sore is in your mouth, it's likely a canker sore. If it's outside the mouth, it's probably a cold sore. If you aren't sure — don't worry. See your doctor or dentist so that they can determine what it is and recommend the proper treatment.

Canker Sore (Aphthous Ulcer)

Written by WebMD Editorial Contributors

Medically Reviewed by Sabrina Felson, MD on May 12, 2021

What Is a Canker Sore?

A canker sore is a small, shallow open wound (or ulcer) in your mouth that can make eating and talking uncomfortable. They’re also known as aphthous ulcers. There are a few types of canker sores:

Minor canker sores. These may show up three or four times a year. They typically happen in people ages 10 to 20. They’re less than 1 centimeter across and heal in about a week with no scarring.
Major canker sores. These are less common. The ulcers are bigger and can last more than 2 weeks. They often heal with scarring.
Herpetiform canker sores. These are rare and show up as clusters of tiny ulcers. They usually heal in about a week.

Canker Sore Causes and Risk Factors

Doctors don’t know what exactly causes most canker sores.

Things that might cause minor sores include:

Stress
Tissue injury, like from a sharp tooth or a dental appliance
Certain foods, including citrus or acidic fruits and vegetables (such as lemons, oranges, pineapples, apples, figs, tomatoes, and strawberries)
Nonsteroidal anti-inflammatory drugs like ibuprofen
An allergy to something in your food or in your toothpaste or mouthwash
Helicobacter pylori, the bacteria that can cause peptic ulcers

Things that might cause complex canker sores include:

An underlying health condition like a weakened immune system, HIV/AIDS, lupus, or Behcet’s disease
Nutritional problems like too little vitamin B12, zinc, folic acid, or iron
Gastrointestinal diseases like celiac or Crohn’s

About 1 in 5 people gets canker sores regularly. They’re more common in women, possibly because of hormonal differences. They may also run in families.

Canker Sore vs. Cold Sore

Canker and cold sores aren’t the same.

Cold sores, also called fever blisters or herpes simplex type 1, are groups of painful, fluid-filled blisters. Unlike canker sores, a virus causes cold sores, and they’re highly contagious. Also, cold sores typically appear outside your mouth -- usually under your nose, around your lips, or under your chin -- but canker sores show up inside your mouth.

Canker Sore Symptoms

You may have a canker sore if you have:

A tingling or burning sensation, often 6 to 24 hours before a canker sore
Small sores in your mouth that are round or oval, white, gray, or pale yellow with a red edge or border
A painful sore or sores that appear alone or in clusters inside your mouth: on your tongue, at the base of the gums, on your soft palate (the back portion of the roof of your mouth), or inside your cheeks

Severe canker sore attacks may also cause:

Fever
Fatigue
Swollen lymph nodes

Canker Sore Diagnosis

Canker sores usually aren’t serious. Call your dentist if you have:

Unusually large sores
Sores that spread
Sores that last 3 weeks or longer
Extreme pain despite avoiding trigger foods and taking over-the-counter pain medication
Trouble drinking enough fluids
A high fever with canker sores
Frequent or lasting mouth sores, which may be a sign of an underlying problem, such as a serious skin disorder called pemphigus, celiac disease, inflammatory bowel disease, Behcet's disease, autoimmune disease, anemia, HIV, or, in rare cases, oral cancer or leukemia

They can usually make a diagnosis based on a physical exam and your medical history. They might want to test your blood to see whether a vitamin deficiency or another health condition is causing the sores.

Canker Sore Treatment

Pain from a canker sore tends to get better in a few days, and the sores usually heal without treatment in about a week or two. Treatment for large, long-lasting, or unusually painful sores might include:

Mouthwashes. Your doctor can prescribe a rinse that has a steroid or a painkiller.
Topical medications. Your doctor may prescribe a topical medication containing a steroid for the inflammation, and a topical analgesic like lidocaine to relieve pain. Aphthasol, a prescription ointment described as an "oral paste," may reduce pain and healing time.
Oral medications. The ulcer drug sucralfate (Carafate) and the gout drug colchicine (Mitigare) can also treat canker sores. Or your doctor might give you steroid pills.
Nutritional supplements. You might need these if a nutrient deficiency is causing your canker sores.
Cautery. Dental lasers can help you feel better right away. Your doctor can also cauterize sores with chemicals like debacterol or silver nitrate.

Canker Sore Home Remedies

Home treatments to speed healing and help you feel better include:

Topical products. Medicated gels, creams, pastes, and liquids go on the sore.
Mouth rinses. Mix salt or baking soda in warm water, and swish it around your mouth.
Milk of magnesia. Put a bit on a cotton swab, and dab it on the sore.

Canker Sore Prevention

There’s no cure for canker sores, and they often come back. But you might get them less often if you:

What is the difference between a canker sore and a cold sore?

Fever Blisters (also known as cold sores) are painful fluid-filled sores that form on the outside of the mouth around the lips. Fever blisters are very contagious. Canker Sores are painful white or yellow sores that only form inside the mouth, usually on the insides of the cheeks or lips or on the tongue.

The oral lesions caused by canker sores and cold sores may appear and feel similar, but they actually have different causes. Canker sores occur only in the soft tissues of the mouth, such as on your gums or inside your cheeks.

What causes a canker sore?

Food sensitivities, particularly to chocolate, coffee, strawberries, eggs, nuts, cheese, and spicy or acidic foods. A diet lacking in vitamin B-12, zinc, folate (folic acid) or iron. An allergic response to certain bacteria in your mouth. Helicobacter pylori, the same bacteria that cause peptic ulcers.