Canker sores, medically known as aphthous ulcers, are common, painful lesions that develop exclusively on the soft tissues inside the mouth. They appear as small, round, or oval ulcers with a distinct white or yellowish center surrounded by a bright red, inflamed border. These sores form on the inner surfaces of the cheeks and lips, on the tongue, or at the base of the gums.
A canker sore should not be confused with a cold sore, which is caused by the highly contagious herpes simplex virus (HSV-1). Unlike cold sores, which typically appear on the outside of the mouth, canker sores are not infectious and cannot be transmitted to another person.
The Role of Stress in Canker Sores
While emotional stress does not directly cause canker sores, it functions as a significant predisposing factor that can trigger an outbreak. The relationship is rooted in the body’s physiological response to high levels of psychological strain. During periods of intense stress, the body releases elevated levels of hormones like cortisol and adrenaline.
This hormonal surge is known to temporarily suppress the immune system’s efficiency, making the oral mucosa more susceptible to minor damage or the effects of existing bacteria. When the immune system is less robust, it may fail to prevent a minor injury from developing into a full-blown aphthous ulcer.
Stress can also induce behavioral changes that physically initiate the sore’s formation. Many individuals under pressure subconsciously develop habits such as biting the insides of their cheeks or lips, or they may begin brushing their teeth too aggressively. This minor trauma creates a small break in the delicate oral tissue, providing an entry point for the condition to take hold.
Other Common Triggers
The presence of canker sores is often linked to factors entirely separate from psychological state, most notably physical trauma to the mouth. Accidental biting of the cheek or tongue is a frequent culprit, as is irritation caused by ill-fitting dental appliances like braces or dentures. Even routine activities, such as rough brushing with a stiff toothbrush, can create the small abrasion needed for a sore to form.
Dietary factors also play a substantial role, particularly sensitivities to certain foods. Highly acidic foods, including citrus fruits, tomatoes, and some spices, are known to irritate the mucosal lining, potentially triggering an outbreak. Other common food triggers include chocolate, coffee, nuts, and certain cheeses.
Furthermore, a lack of specific micronutrients can predispose an individual to developing canker sores. Recurrent episodes are sometimes associated with deficiencies in:
- Folic Acid
- Iron
- Vitamin B12
- Zinc
Chemical irritants found in common oral hygiene products, specifically Sodium Lauryl Sulfate (SLS), a foaming agent in some toothpastes, have also been identified as potential triggers.
Treatment and Relief Strategies
Once an aphthous ulcer has developed, the primary goal of treatment is to manage the pain and accelerate the natural healing process. Over-the-counter topical anesthetics containing ingredients like benzocaine or lidocaine can be applied directly to the sore to provide temporary pain relief. For more severe or persistent cases, a dentist or doctor may prescribe a mouth rinse containing a steroid like dexamethasone to reduce inflammation.
Simple home rinses are effective in soothing the irritation and keeping the area clean. A mixture of salt dissolved in warm water, or a baking soda rinse, can help dry out the sore and encourage healing. It is advisable to temporarily switch to a toothpaste that does not contain the irritant Sodium Lauryl Sulfate and to avoid mouthwashes that contain alcohol, which can cause further discomfort.
During the healing period, avoiding acidic, spicy, or crunchy foods is important to prevent additional irritation and pain. While most minor canker sores resolve on their own within one to two weeks, a medical professional should be consulted if the sores are unusually large, last longer than two weeks, or occur with high frequency.