Canker Sores: A Closer Look at These Mysterious Ulcers

Canker sores can be incredibly frustrating, making everyday activities like eating and speaking uncomfortable. Most of us have experienced these painful mouth ulcers at some point, yet they remain a mystery today since the exact cause is still unknown.

In this article, we’ll dive into the facts about canker sores and share essential tips to help you deal with them effectively.

What are Canker Sores?

Canker sores, also known as Aphthous Stomatitis, are common mouth ulcers that can make life a bit uncomfortable. The term "Aphthae" comes from the Greek word Aphthi, meaning "to set on fire," while "Stomatitis" simply refers to inflammation of the mouth.

These sores typically appear on the soft tissues inside the mouth, such as the inner lips, cheeks, tongue, roof of the mouth (palate), and gums. Some areas, like the gum line and the front part of the palate, are less prone to canker sores because they have a thicker protective layer called keratin.

Nearly everyone experiences canker sores at some point. For some people, they occur more frequently, with multiple outbreaks each year. This condition is known as Recurrent Aphthous Ulcers and affects about 25% of the population. The good news is that canker sores aren’t contagious, so they can’t be spread to others.

These ulcers can vary in size, shape, and appearance—ranging from small, round or oval sores to larger clusters. Although they typically heal on their own, more severe outbreaks may take longer to go away.

The Stages of Canker Sores

Canker sores go through four stages.

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?

The white or yellow coating you see on a canker sore is actually the result of dead cells shedding from the lining of your mouth.



When your immune system overreacts to certain triggers, like specific foods or chemicals, it releases inflammatory molecules that can damage the cells in your mouth, leading to the formation of an ulcer.

The red border around the sore is a sign of ongoing inflammation, which is responsible for the burning sensation you feel. This is why the main goal of treatment is to control the inflammation, as it helps reduce pain and speeds up the healing process.

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 just one type of mouth ulcer, but not all mouth ulcers are canker sores. Various oral and general health conditions can cause similar lesions in the mouth. Here are a few worth noting:

• 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.