Canker Sores: Types, Causes & Treatment


What Are Canker Sores?

A canker sore is also known as aphthous ulcer is a small, shallow, painful, open wound in the mouth or at the base of your gum which makes eating and talking uncomfortable. Unlike cold sores, canker sores do not occur on the surface of your lips and are not contagious.

Types of Canker Sores

Minor Canker Sores

This type of canker sore shows up three or four times a year. They are generally small and are oval-shaped with a red edge. They occur in people between the ages of 10 to 20. There are less than one centimeter across and heal in about a week without any scarring.

Major Canker Sores

This type is less common. Unlike the minor canker sores, these are larger and deeper. They also have a round shape with defined borders, but may have uneven edges when extremely large. It can also be unbearably painful. It can also take up to six weeks to heal and can leave extensive scarring.

Herpetiform Canker Sores

They are also less common like the major canker sores and usually develop later in life. These canker sores are also small-sized and are often in clusters of 10 to 100 sores, but may merge into one large ulcer. They have irregular edges and can heal within a week or two without scarring.

Causes and Risk Factors of Canker Sores

The main cause of most canker sores is unidentified, however, the factors that might cause minor sores are:

  • Stress
  • Having a tissue injury from a dental appliance or sharp tooth
  • Allergy to a food or toothpaste/mouthwash
  • Certain foods; citrus or acidic fruits and vegetables such as apples, pineapples, oranges, lemons, strawberries, etc.
  • Nonsteroidal anti-inflammatory drugs like ibuprofen
  • Immune system problem
  • Menstrual cycle
  • Helicobacter pylori, the bacteria that causes peptic ulcers

Here are factors that may cause complex canker sores:

Inadequate consumption of healthy nutrition

  • low levels of folic acid, iron, or vitamin B12
  • underlying health conditions such as HIV/AIDS
  • weak immune system
  • gastrointestinal diseases such as Crohn’s

Symptoms of Canker Sores

sore throat

  • Small sores in the mouth which are oval or round, white, gray, or pale yellow with a red edge
  • Tingling or burning sensation, which develops 6 to 24 hours before a canker sore
  • A painful sore that appears alone or in clusters inside the mouth, at the base of the gums, on the tongue, inside the cheeks, or on the soft palate
  • Fatigue
  • Swollen lymph nodes
  • Fever
  • Sores that spread
  • Large sores
  • Sores that can last 3 weeks or more
  • Difficulty drinking enough fluids
  • Frequent mouth sores which may be a sign of an underlying condition such as inflammatory bowel disease, leukemia, Behcet’s disease, among others

Canker Sores Vs Cold Sores

  • Canker sores appear inside the mouth, while cold sores appear outside the mouth; usually under the nose, under the chin, or around the lips
  • Canker sores appear as white circles with a red edge while cold sores are normally fluid-filled blisters.
  • Canker sores are not infectious; cold sores are infectious.

How to Diagnose Canker Sores

A canker sore can be diagnosed through an examination of the sore. Your doctor may order blood tests or take a sample tissue of the area if there’s a severe breakout or if they think you might have:

  • a virus
  • a vitamin or mineral deficiency
  • a hormonal disorder
  • a problem with your immune system
  • a severe breakout

The cancerous lesion can also appear as a canker sore, but can’t heal without treatment. Some symptoms of oral cancer are similar to those of canker sores, such as swelling and painful ulcers in your neck. However, oral cancer is often identified by rare symptoms such as

  • Lose of teeth
  • Bleeding from the mouth or gum
  • Difficulty swallowing
  • Having earaches

Complications of Canker Sores

If you leave a canker sore untreated for a few weeks or more, you are most likely to experience other, more severe complications, such as:

  • Pain or discomfort while talking, eating, or brushing your teeth
  • Fatigue
  • Sores spreading outside of your mouth
  • Fever
  • Bacterial infection

How to Treat Canker Sores

Most times, treatment isn’t necessary for minor canker sores, because they tend to clear on their own in a week or two. Here are some treatment options for canker sores:

Mouth Rinse

Your doctor may prescribe a mouth rinse containing the steroid dexamethasone to reduce pain and inflammation or lidocaine to also reduce pain if you have several canker sores.

Over-the-counter Products

Over-the-counter and prescription products such as pastes, creams, gels, or liquids may help relieve pain and speed healing if applied to individual sores as soon as they appear.

Some of these products have active ingredients, such as:

  • Hydrogen peroxide (Orajel Antiseptic Mouth Sore Rinse, Peroxyl)
  • Benzocaine (Anbesol, Kank-A, Orabase, Selectin-B)
  • Fluocinonide (Lidex, Vanos)

Oral Medications

SchizophreniaOral medications can be used when canker sores are severe or do not respond to over-the-counter treatments. Some of these medications include:

  • Medications not made to treat canker sores, such as the intestinal ulcer treatment sucralfate (Carafate) used as a covering agent and colchicine, which is normally used in the treatment of gout.
  • Oral steroid medications used when severe canker sores don’t react to other treatments. Because of serious side effects, these are usually the last resort.

Cautery of Sores

During this procedure, a chemical substance or an instrument is used to destroy, burn or sear tissue.


This is a topical solution made to treat canker sores and gum-related issues. Chemically cauterizing these canker sores will help reduce healing time to about a week.

Canker sores that aren’t serious normally cure on their own. Prescribed treatments can help with more severe or recurrent ulcers, but they don’t “cure” them. Canker sores should be brought to a dentist or doctor’s attention if they:

  • Continue without improvement for at least 2 weeks
  • Get worse – even if you’re using home cures to help
  • Recur frequently (at least twice a year) or are especially numerous or severe
  • If other symptoms such as fever, diarrhea, headache, or skin rash are present

Alternative Treatments for Canker Sores

Alternative canker sore treatments aim to heal existing sores and prevent them from recurring.

  • Calendula (Calendula officinalis), myrrh (Commiphora molmol), and goldenseal (Hydrastis canadensis) are among the herbal medicines that can cure existing sores.
  • Compresses soaked in teas are immediately applied to the wounds.
    When a wet tea bag is used as a compress, the tannic acid in the tea bag can help dry out the sores.
  • Dandelion (Taraxacum officinale) tea or capsules may aid in the healing and prevention of sores.
  • Over-the-counter versions of home medicines and herbal medications for pediatric patients may not be readily available.

How to Prevent Canker Sores

Maintain Oral Hygiene

Consistent brushing after meals and flossing once a day can keep your mouth free and clean of foods that might cause a sore. Make use of a soft brush to help avoid irritation to sensitive mouth tissues, and also avoid toothpaste and mouth rinses that contain sodium lauryl sulfate.

Watch What you Eat

There are foods you eat that can irritate your mouth; try to avoid foods such as nuts, chips, pretzels, certain spices, salty foods, and acidic fruits such as oranges, pineapple, and grapefruit. Also, try to avoid any foods to which you’re sensitive or allergic. Instead, eat plenty of fruits, whole grains, and vegetables to help prevent nutritional deficiencies.

Protect your Mouth

Seek a dentist’s assistance if you have braces or other dental appliances, and ask about orthodontic waxes to cover sharp edges.

Reduce Stress

Learn and use stress-reduction techniques such as meditation and guided imagery if your canker sores are related to stress.

Now that you Know…

Canker sores are not life-threatening, although they can cause one to feel uncomfortable and be in pain. It could also be as a result of an underlying disease that one may have, that is why when one develops weird and persistent symptoms such as fever, difficulty swallowing fluids, fatigue, and large sores, they should consult a doctor immediately to help examine the possible disease associated with it because bacterial infections and create more serious issues.