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Canker Sores and Stress: Understanding the Connection

8 min read
by Dylan Hao |

You’ve been preparing for a big day for a while now, and it’s almost here. Your clothes are cleaned and ironed, your research is done, and everything is good to go.

Except, out of nowhere, you wake up, look in the mirror, and come face-to-face with … a canker sore.

Where did it come from? How can you get rid of it, like, now?

Many people don’t realize there’s a direct link between canker sores and stress. 

What’s the connection between stress and canker sores, and how can you avoid them? This blog has all the answers you need to prevent and eliminate the dreaded canker sore.

What Are Canker Sores?

The official term for these annoying little white sores is “aphthous ulcers.” They’re one of the most common medical issues out there, with nearly one in ten people affected. When they show up frequently, they’re called “recurrent aphthous stomatitis” (RAS).

Canker sores attack the mucous membranes along the mouth, creating shallow lesions at the base of the gums or along any of the inner soft tissue, especially the cheeks and behind the lips.

Because of the placement, if you have a deeper or more stubborn sore, it makes chewing and talking difficult. 

Canker Sores Are Not Cold Sores; Here’s Why

Many people don’t realize the night and day difference between canker sores and cold sores. They look similar, but they’re distinctly unalike.

Cold sores, also known as “fever blisters,” form on the edges of the lips around the outside of the mouth. They also have red borders, but are full of fluid and highly contagious. 

Cold sores are caused by a form of the herpes simplex virus, usually type 1 (HSV-1). But if you have this condition, don’t worry — many people get infected and never show symptoms. The virus hides out in the nerve cells, never going away and occasionally becoming active again.

If you have fever blisters, you’ll notice sores outside the mouth that feel like they burn or tingle. They may be accompanied by symptoms similar to other viruses, like swelling of the lymph nodes, tiredness, and fever, hence the “fever blister” name.

Types of Canker Sores

While cold sores result from an incurable virus, canker sores have a variety of random potential causes, depending on the type. There are three main kinds of canker sores:

  • Minor
  • Major
  • Herpetiform

Regardless of the type, you may feel tingling or burning in the area just before the sore breaks through the skin surface.


Minor canker sores are the most common, appearing oval-shaped with slightly red edges. They’ll go away within a week or two.


Major canker sores develop deeper in the skin and are bigger than the minor types. They’re typically round but can also have varied edges.

While minor canker sores are irritating, major ones can be downright painful, taking up to six weeks to heal. When they do finally go away, they can leave scars.


Herpetiform canker sores are rare. Those who have them usually get them later in life. Although they have the “herp” prefix, they’re not linked to the virus. 

These sores are tiny — the size of a pinpoint — but show up in outbreaks of 10 or more in a group, sometimes as many as 100. 

After herpetiform canker sores develop, they can spread and become one large one. They’re not fun, but they, too, tend to heal on their own within a week or two without scarring.

Causes of Canker Sores

So what causes these irritating, sometimes painful lesions? Scientists don’t have an exact answer.

It could be a deficiency in iron, Vitamin B12, or folic acid. Or, they could come from an injury or tobacco habit. One fact we do know is that there’s a direct link between canker sores and another thing we all have in common — stress.

Stress and Its Effects on the Body

If you ask a dozen people what they think “stress” means, you’ll likely get a dozen different answers. In research analysis terms, stress refers to a concept that includes any challenging circumstance.

This is called a “stressor.” How our bodies respond to stressors physiologically and psychologically is our “stress response.”

Although stress is a scientific concept, the combination of stressors and stress responses differs for everyone. You can put two people in the same situation with the same stressor, and their mental and physical responses won’t be the same. Some people will freeze, others will flee, and still others will fight. 

There are two main types of stress: acute and chronic.

Acute stress lasts for short times, during which the amygdala in our brains prepares us for “fight or flight.” Chronic stress is a long-term situation or environment that our bodies become accustomed to, adjusting physically and mentally to account for it.

Stress and the Immune System

Typically, involuntary physical responses occur as the nervous system releases stress hormones like adrenaline and cortisol. You’ll notice a rapid heartbeat, tight muscles, fast breathing, and possibly pounding in your ears due to rising blood pressure. You may even notice certain senses increasing as your focus on the situation becomes laser-sharp.

But regardless of whether you’re dealing with acute or chronic stress, one of our bodily systems that become affected is the immune system.

Your immune system is a combination of cells, proteins, tissues, and organs that protect your external and internal parts from harm due to damage or disease.

The immune system’s response is different during acute versus chronic stress.

Acute Stress Responses

While under acute stress, the body puts specific cells into action, sending them into the bloodstream to prepare for potential injury or infection. 

Pro-inflammatory cytokines are released to help speed up healing if there is damage, as inflammation can protect an injured area while the cells attempt healing.

The Dangers of Chronic Stress

The dangers of chronic stress (young woman seated at a table holding her head in her hands)

On the other hand, chronic stress can last for days, months, or years. The body still releases those cytokines, but long-term inflammation is dangerous. It reduces the immune system's effectiveness and increases your risk of developing chronic diseases. 

Ongoing stress shows up in less obvious ways, such as jaw clenching and teeth grinding (bruxism), as the body attempts to release the buildup of excess hormones.

These symptoms of stress can be mild and annoying all the way up to severe and dangerous, including cardiovascular disease, stroke, diabetes, and other potentially deadly conditions.

You can easily reduce the damage from bruxism by using a custom-fit night guard, like those we create at JS Dental Lab, while you’re figuring out how to reduce your stress. But other side effects brought on by your ongoing stressors aren’t as simple to solve.

If you’ve been dealing with chronic stress, it’s important to talk to your healthcare provider to get medical advice and reduce the impact of those hormonal changes on your body before the damage becomes permanent.

The Link Between Canker Sores and Stress

With acute or chronic physical or emotional stress, this elevated adrenaline and cortisol, alongside a reduced immune system, can bring on those mouth ulcers we know as canker sores.

The development of canker sores is intrinsically linked to hormonal changes caused by stress. But the level of anxiety one person feels in a situation isn’t always the same as someone else’s, which is why you may have canker sores show up before a big event while your friend or spouse isn’t stressing it at all.

How we respond to stress is based on a combination of various factors, including genetics, our childhood environments, current situations, how big the stressor is, and whether we have any vitamin deficiencies. 

Risk Factors for Canker Sores

Some risk factors predispose certain people to canker sores during stressful times. Their causes are still unknown for sure.

Yet, in the fields of medicine and dentistry, specialists have noticed certain consistent things that increase your chances of developing these sores:

  • Women are more apt to get canker sores during their menstrual cycles.
  • Children have cold sores more frequently than adults.
  • Children with parents with recurrent lesions are more likely to develop them.
  • If you’re allergic to specific foods, a canker sore can result. 
  • Smokers have more cold sores than non-smokers.
  • Vitamin deficiencies alongside weakened immune systems will almost certainly mean a cold sore at some point.

The Stress Connection

These factors may seem unrelated, but they do have a connection — how your body handles stress.

For instance, a lack of Vitamin D increases your chances of depression and anxiety and weakens your immune system. Together, those factors are a recipe for a canker sore outbreak.

Studies show that people with RAS have higher levels of anxiety and depression. However, there isn’t a clear reason why this is the case. Some scholars suggest that stress victims often bite their lips and cheeks. Others point to the weakened immune system that almost always occurs when we’re stressed out.

No matter the reason, if stress triggers your canker sore outbreaks, you want to know how to fix it. 

Read more: Reasons You May Be Biting Your Tongue in Your Sleep

How to Manage Canker Sores and Stress

Young woman reading on a couch

If you think your canker sores are caused by your body’s reaction to stress, learning stress management techniques could reduce your flare-ups.

Even better, relieving stress helps your overall health, improves your immune system, and can even aid in reducing gum disease and tooth decay.

When you already have active sore outbreaks, they may heal faster if you avoid things that irritate the canker. Skip toothpaste with sodium lauryl sulfate and, of course, acidic and spicy foods that could increase your pain.

Over-the-counter treatment options come in gels and mouth rinses. These can reduce discomfort and speed up healing, but they won’t help prevent the canker sores in the first place. That is an internal process, and it all starts by relieving your body of as much stress as possible.

Stress Management

Just as everyone handles challenges differently, we all have various things that reduce our stress levels. Some work consistently, such as taking deep breaths to slow your heart rate, lower your blood pressure, and chill that “fight or flight” process. This can be done randomly when you notice you’re starting to get stressed, or in controlled environments like meditation and yoga.

Other common stress management techniques include journaling, exercising, and spending time in nature. Whatever you do that makes you feel noticeably calmer — even if it’s reading a book or talking to your friends — try doing it more often.

If your stress load is consistently high, it may be time to try cutting out whatever’s causing it. To do so, you may need to do one of the following:

  • Look for a new job.
  • Get mental health counseling.
  • Change your diet.

Some steps can make a big difference.

As the metaphor goes, you can’t put on someone else’s oxygen mask if you can’t breathe yourself. Take time throughout the week to do things you enjoy, or sit in peaceful silence and let your brain recharge.

If none of those tips helps, it’s okay to seek professional assistance. Talk to your doctor or therapist about your feelings. Find out what your options are, and be open to their suggestions.


The connection between stress and canker sores is easy to see once you understand what’s happening below your body’s surface. Stress plays a big part in your overall physical and mental well-being. 

Now that you understand the impact of stress on your body, reach out and take the first step to heal — and enjoy a life with fewer canker sores.

Some of those consequences can be helped with a custom night guard we can make you at JS Dental Lab

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