Canker Sores: A Closer Look at These Mysterious Ulcers

Canker sores are something most of us have dealt with. Still, they remain a mystery today as we're not entirely sure what causes them and why they happen. But don't worry, in this article, we're going to demystify canker sores and give you all the essential and available information you need.

What are Canker Sores?

Canker sores, also known as Aphthous Stomatitis, are common mouth ulcers that can make your life a bit uncomfortable. "Aphthae, derived from the Greek word 'Aphthi,' meaning 'to set on fire,' and 'Stomatitis,' referring to the inflammation of mouth tissues.

They target the soft lining of your mouth, like the inside of your lips and cheeks, your tongue, the roof of your mouth (palate), and the base of your gums below your teeth. However, the areas around the gum line and the front portion of the palate are not vulnerable. The reason is that these have a protective shield called keratin.

Almost everyone will experience these unpleasant sores at some point in life. For some, it's more frequent, with multiple outbreaks each year. This is called Recurrent Aphthous Ulcers, and it affects about 25% of the world's population (3). The good news is, they're not infections, so you can't spread them to others.

These ulcers can vary in appearance, size, and shape from small round or oval sores to larger and more numerous ones. They usually heal on their own, but the more severe the outbreak, the longer it takes for them to go away.

The Stages of Canker Sores

Canker sores have four stages, and it's helpful to identify them to know what to expect.

First, there's the Prodromal Stage, which happens about a day before the canker sore shows up. You might feel itching or tingling in that spot.

Then comes the Macule Stage, where you'll notice a red spot that might have a white dot in the center. This is a sign that inflammation is intensifying.

Next is the Ulcer Stage, when the actual sore appears. It's small, painful, and results from the death of superficial mouth cells.

Finally, there's the Healing Stage, which usually takes about 7 to 10 days. During this phase, the pain eases, and the canker sore gradually disappears, leaving no scar.

What is this White Stuff that Covers the Ulcer?

Now, you might be wondering about that white or yellowish stuff coating the canker sore. Well, it's a result of a complex process involving your immune system, genetics, and environmental factors like stress and nutrition.



When immune cells overreact to something (like certain foods or chemicals), they release inflammatory molecules that can damage mouth cells. This leads to the formation of an ulcer, and the white substance is essentially dead cells peeling off.

The red border you notice around the sore is a signal of the inflammation happening, and this is what causing the burning sensation. That's why the primary goal of treatment is to manage this inflammation, which helps reduce pain and promotes faster healing.

The Different Types of Canker Sores

Canker sores come in various forms:

1. Minor ulcers: These are the most common, occurring in about 80% of cases. They're usually small, with one or up to five at a time, measuring between 2 and 10 millimeters. The good news is they heal on their own in about a week or so, and they typically don't leave any scars.


2. Major ulcers: This type is rarer and more severe. The ulcers are deeper and can reach significant sizes, sometimes up to 5 centimeters. You might have one or up to three at a time, and they take longer to heal, often leaving a scar. Major ulcers can sometimes signal HIV infection (5).


3. Herpetiform ulcers: These are similar to minor ulcers, but they can be numerous, sometimes up to a hundred. They're small and appear in clusters all over your mouth. They are often mistaken for herpes infections due to their similar look.

What Causes Canker Sores?

The exact cause of canker sores isn't entirely clear, but several factors are thought to play a role:

• Genetics: It's not uncommon for people who get frequent canker sores to have family members with the same issue.


• Stress: If you've been through a stressful period, it can weaken your immune system, making you more vulnerable.


• Nutritional deficiency: Certain nutrients, like B-complex vitamins and iron, are crucial for healthy cell function. Lack of these nutrients might be contributing.


• Injury or trauma: Accidentally biting your lips or brushing your teeth too vigorously can lead to a type of ulcer known as traumatic.


• Allergies: Allergies to certain foods or substances can also be the culprit.


• Weak immune system: Conditions like HIV, cancer treatment, and certain medical conditions can weaken your immune system and increase the likelihood of developing canker sores.

Other Oral Conditions that Resemble Canker Sores

Canker sores are a type of mouth ulcer, but not all mouth ulcers are canker sores. Many oral and general health conditions can lead to similar lesions in the mouth. Here are some to be aware of:

• Traumatic ulcers: These are caused by physical or chemical injury or trauma, such as using a harsh mouthwash, biting your mouth tissue, or consuming something too hot. Traumatic ulcers are often larger with irregular borders and typically lack the characteristic red halo.


• Herpetic ulcers or cold sores: These are caused by the Herpes Simplex Virus. Factors like stress, sun exposure, or a weakened immune system can trigger the virus, resulting in painful mouth lesions, often affecting the lips. They start as small blisters that soon break open to form painful ulcers.


• Pemphigus vulgaris: This is an autoimmune condition that affects the skin and mucous membranes, including the mouth. It begins as blister-like lesions filled with clear fluid that eventually rupture, leaving painful ulcers.


• Behcet’s syndrome: A rare and poorly understood condition that causes inflammation of blood vessels and tissues, often leading to mouth and genital ulcers, along with other symptoms like eye issues, acne, and joint pain. Seek immediate medical attention if you notice several of these signs.


• Crohn’s disease: An inflammatory condition of the digestive system that can manifest as canker sores in the mouth. Remember that anything affecting the gut can also impact the mouth. Other associated symptoms include diarrhea, stomach pain, fatigue, and weight loss.


• Oral cancer: One of the signs of oral cancer is an ulcer that doesn't heal even after several weeks. In such cases, it's vital to seek a medical examination to rule out serious concerns.

How to Treat Canker Sores?

The not-so-great news is that there's no magic cure to make canker sores disappear instantly. But the good news is, they often heal on their own without needing any treatment.

If you're dealing with frequent canker sores, the first step is to identify the possible cause. It could be a lack of essential vitamins or minerals, stress, allergies, infection, or an underlying medical condition.

Symptomatic treatments:

While waiting for canker sores to heal, some treatments can provide relief, prevent infection, and speed up healing. Here are some common options:

• Numbing gels for pain relief: These contain active ingredients that help numb the area to ease discomfort. Over-the-counter products include Orajel and Canker-X Mouth Sore Gel.


• Mouthwash for pain relief and healing: Antiseptic mouthwashes can reduce the bacterial load in your mouth and prevent infection. Look for alcohol-free options like Orajel mouth sore rinse and Colgate peroxyl mouth rinse, which are both peroxide-based and alcohol-free.

When to See a Dentist for Canker Sores

If you encounter any of the following situations with your canker sore, it's time to schedule a visit to the dentist:

• Severe form: If your canker sore is too large, deep, and extremely painful, your doctor may consider other options such as topical corticosteroids, oral corticosteroids, or laser therapy.


• Recurring or Non-Healing Sores: If the canker sore keeps coming back or refuses to heal despite your best efforts, it may be an indicator of an underlying issue that requires professional attention.

If the canker sore persists despite more advanced treatments, your doctor may recommend a biopsy. During a biopsy, a small portion of the ulcer is removed and examined under a microscope to determine its nature, whether it is benign or potentially cancerous.