Canker sores are ulcers that develop inside the mouth and are the most common type of mouth ulcer. Canker sores can be painful, and they cause discomfort while eating and drinking.

They are often confused with cold sores, which are blisters that form as a result of a viral infection on the outside of the mouth. Canker sores are not contagious like cold sores, and they can heal with treatment within a few weeks. 

Canker Sore Symptoms

Canker sore symptoms vary from other mouth ulcers or sores. A canker sore appears as a small white or yellow oval-shaped ulcer within the mouth cavity.


You will also notice a painful, red area in the mouth and a tingling sensation. Many people also report experiencing swollen lymph nodes, fever, and feeling ill. The symptoms of a canker sore last a few weeks in most cases, but severe cases can last up to six weeks, even with treatment. 

Canker Sore Causes

In many cases, the cause of a canker sore can not be identified. If you have a family history of canker sores, you will have a greater risk of developing them. 

In addition to this, there are a number of conditions that are associated with canker sores.

♦ Viral infections can cause recurrent canker sores, so repeated canker sore appearance can indicate a systemic illness.

♦ Immunodeficiency disorders, such as Behcet’s disease, can cause blood vessel inflammation that leads to the development of canker sores.

♦ Vitamin or mineral deficiency can cause canker sores, specifically vitamin B-12, iron, folic acid, and zinc deficiencies. Calcium deficiencies do not cause canker sores but can make them worse. 

♦ Food allergies or allergic reactions to bacteria can cause mouth ulcers (canker sores) and peptic ulcers. Avoiding foods you are allergic to can prevent these ulcers from developing.

♦ Hormonal disorders, including menstruation, can lead to imbalanced hormone levels, which contribute to canker sore development.
Stress does not necessarily cause canker sores, but it can make them worse. In a time of high stress, canker sores are common and can become easily irritated with eating, drinking, and talking.

♦ Mouth injury causes damage to the delicate tissues in your mouth as well as inflammation. As a result, a canker sore can develop but should go away quickly so long as they are not irritated. 

Diagnosis of Canker Sores

A canker sore can be diagnosed on appearance. Your doctor may take a blood test or biopsy if you have a severe breakout. 

These tests are done when doctors believe you may have a viral infection, hormonal disorder, nutrient deficiency, or issues with your immune system. Some cancerous lesions are similar to canker sores, so it is important to have any sore in your mouth examined by a doctor. 

Oral cancer will typically present as mouth ulcers along with: 

♦ Loose teeth
♦ Earaches
♦ Bleeding from the gums or mouth
♦ Trouble swallowing

Canker Sore Treatment

There are several approaches available for treating and preventing canker sores. Most canker sores will heal without treatment, but there are lifestyle changes you can make to help ease symptoms. 

♦ Brush your teeth regularly to avoid bacterial infection.
♦ Drink milk or eat yogurt to reduce pain in the mouth.
♦ Avoid spicy foods to allow for quicker healing.
♦ Gargle with salt water to relieve pain and clear away bacteria.
♦ Rinse your mouth with a mixture of warm water and baking soda.

There are also topical ointments your doctor can prescribe to help alleviate pain, including:

♦ Prescription mouthwashes
♦ Antibiotics to clear up any bacterial infection that could be causing the canker sore
♦ Antimicrobial mouth rinses
♦ Corticosteroid ointment to reduce swelling and inflammation for tender canker sores

Natural Treatment for Canker Sores

In addition to lifestyle changes and medical ointments, there are natural treatments you can use for canker sores.

♦ Zinc helps the healing of canker sores and can support immune system health to reduce their development. Zinc, as a supplement, applied topically or as a lozenge, works to reduce healing time. It also boosts the immune system, allowing it to better fight infections that trigger the development of canker sores.

L-lysine is a natural amino acid that works in a similar way to zinc. This amino acid is essential, and you need to get this from food. As a supplement, l-lysine heals canker sores and reduces the risk of their recurrence. L-lysine also reduces inflammation in the body, which can trigger canker sore outbreaks.

Probiotics can also reduce the occurrence of canker sores. While these sores are caused by viral infections, probiotics support the immune system. In doing so, the body is better equipped to fight infections, which can reduce canker sore development.

How to Prevent Canker Sores

If you know what triggered the initial outbreak of a canker sore, you can prevent their recurrence. Typical triggers include spicy, acidic, or salty foods, as well as foods you may have an allergy too. 

Stress can also trigger canker sores, so by practicing stress reduction techniques such as yoga and meditation, you can prevent them from coming back. It is also important to practice good oral hygiene and use a soft toothbrush to avoid irritating sensitive tissues in your mouth. 

When to Talk to Your Doctor

A canker sore that is left untreated for a few weeks can cause serious complications. You should talk to your doctor if you experience unbearable pain that is interfering with your life. 

Bacterial infections can spread and have implications for your health, so it is important to stop bacterial causes of canker sores right away. Contact your doctor if you experience any of the following with your canker sore:

♦ A fever
♦ Cellulitis
♦ Sores spreading to the outside of the mouth
♦ Fatigue
♦ A rash
♦ Headaches
♦ Excruciating pain
♦ Diarrhea

What Is the Long-Term Outlook?

There are three types of canker sores, and the type will determine how long you will have the canker sore. 

Minor canker sores are usually small and heal without scarring within two weeks, and they are the most common form. Major canker sores are larger and deeper and can be extremely painful. They can take up to six weeks to heal. These sores can also leave extensive scarring.

Herpetiform canker sores are uncommon and develop later in life. These are easily identified by their pinpoint size and cluster formations. They heal within two weeks and do not usually leave scarring. 

With prompt diagnosis and following the prescribed treatment plan, canker sores can be cleared up within two weeks in most cases. There are several medical and natural treatment options to help relieve pain and reduce the duration of a canker sore. In rare instances, a canker sore can last longer.

With treatment, you can alleviate discomfort, so it does not interfere with eating or daily living.