Canker Sores

What Are Canker Sores?

Cankers sores are small, shallow ulcers in the lining of the mouth or at the base of the gums. They are one of the most common oral conditions, with over half of the population experiencing canker sores. [1]

In the medical world, canker sores are called “aphthous ulcers” or “aphthous stomatitis.” They tend to affect the softer parts of the mouth like the tongue and cheeks, and canker sores usually recur over time. While canker sores are small and shallow, they can also be very painful and make it difficult to eat and drink. Canker sores typically take 1-2 weeks to heal on their own.

Questions about canker sores? Check out this canker sore FAQs for answers.

Types of Canker Sores

Minor: 80% of cases are minor canker sores, with small sores less than 1 cm in diameter. They heal in about a week and don’t cause scarring. [1]

Major: 15% of patients experience major canker sores, which are larger than 1 cm in diameter, more painful, take 2+ weeks to heal, and can cause scars. [1]

Herpetiform Canker Sores: Fewer than 5% of people experience herpetiform canker sores, which form as clusters of very small ulcers that can merge together into larger sores. Herpetiform canker sores usually heal in about a week like minor canker sores, but may be more painful before they heal. [1]

Symptoms of Canker Sores

Canker sores start as whitish or yellowish spots in the mouth surrounded by redness and irritation. In addition to the pain and discomfort from the sores themselves, people may experience a burning sensation before canker sores appear. In severe cases, people may also experience fever or swollen lymph nodes with canker sore outbreaks. [2] Canker sores don’t pose any greater health risks beyond the pain and discomfort the sores cause. [3]

Identifying Canker Sores

Canker sores may be confused with other small ulcers in and around the mouth, like cold sores, traumatic ulcers, and oral mucositis.

Canker Sore or Cold Sore?

Canker sores only occur inside of the mouth, and they aren’t contagious or caused by the herpes simplex virus. If a sore or ulcer is on the lip or around the mouth, it’s not a canker sore.

Canker Sore or Regular Sore?

By “regular sore” we mean traumatic ulcers, or injuries to the oral mucosa that lead to sore spots similar in look and feel to canker sores. For example, when you accidentally bite the lining of your mouth and develop a sore, that’s a traumatic ulcer, not a canker sore. Other common causes include denture irritation and other oral care injuries. Sometimes mild burns from hot food or drink can also cause painful sores in the mouth.

Canker sores FAQs

Canker Sore or Oral Mucositis?

Oral mucositis or “OM” is a side effect of cancer treatments that causes painful mouth ulcers. Canker sores are not a symptom of chemotherapy or radiation treatments like OM, and canker sores are typically less painful.

What Causes Canker Sores?

The exact causes of canker sores are not well-established, but certain groups of people are more susceptible. Canker sores are most common in children and young adults. They tend to occur more in women than men, especially during the menstrual period. It is also more common to develop canker sores if you have a parent who experiences them. [3]

People who experience canker sores often have an immune disorder like IBS, lupus, celiac disease, ulcerative colitis, Crohn’s disease, AIDS, or Behcet’s disease. [2]

A deficiency in vitamin B-12, zinc, folic acid, or iron may cause canker sores in some adults. [2]

Some people get canker sores (or make existing canker sores worse) by eating acidic foods like citrus fruits or tomatoes. [2]

Canker sores are also a known side effect of using nonsteroidal anti-inflammatory drugs like aspirin and ibuprofen.

Some toothpaste ingredients may cause canker sores in certain people as well. [3]

Canker Sore Treatments

The majority of people who experience canker sores let them heal on their own. In more severe and painful cases, patients use a range of natural and medical solutions to lessen the pain. Light therapy is also showing success limiting pain and speeding healing time in numerous peer-reviewed clinical studies, outlined below.

Medical Treatments for Canker Sores

Common over-the-counter canker sore products like Kank-A®, Zilactin® and Orajel® are used to lessen pain. In more severe cases, antibacterial mouthwashes and/or corticosteroid ointments may be prescribed to reduce pain and irritation. Acyclovir is an antiviral drug that is sometimes prescribed in severe canker sore cases.

Natural and DIY Remedies for Canker Sores

People have reported anecdotal relief with hundreds of natural, at-home, and over-the-counter methods over the years. Gargling salt water for canker sores is an old standard. Other remedies people use include mouthwash, baking soda, hydrogen peroxide, lysine, clove oil, essential oils, honey, vitamin C, vitamin b12, coconut oil, and silver nitrate. None of these methods have been widely tested in clinical trials.

Light Therapy for Canker Sores

Light treatments are also used against canker sores. They don’t come with the potential side effects of drugs, but unlike other at-home treatments, the science behind light treatments and canker sores is well-established in a range of peer-reviewed studies.

One example of a home use light therapy device for cold sores is the Luminance RED Canker Sore Treatment Device.

Clinical Research on Light Therapy and Canker Sores

Hundreds of clinical studies on light therapy and oral health have shown healing and pain relief benefits from specific wavelengths of light. 25+ clinical studies have demonstrated that light therapy significantly reduces pain from canker sores, speeds the healing time of canker sores, and can make it easier for a person to eat, drink, and function normally during a severe canker sore outbreak.

A 2019 study concluded that patients with recurrent canker sores “showed remarkable improvements in reduction of pain, healing time, and lesion size” after light therapy treatments. [4]

Other studies have also found that light therapy treatments can significantly reduce the size of canker sores. [5]

Pain Relief From Canker Sores With Light Therapy

A series of studies over the past two decades have shown significant and often immediate pain relief from canker sores after light therapy sessions. Light therapy treatments have also been almost universally well-tolerated, with few if any reported side effects or complications.

Immediate Pain Relief From Canker Sores

Light therapy studies have consistently demonstrated “immediate” pain relief from canker sores in a majority of patients.

A 2013 study assessed people’s pain from severe canker sores just before and after a light therapy session. Before light therapy, people reported average pain scores of 8-9. Immediately after light was shined inside the mouth, patients reported an average pain score of just 0-1, a dramatic reduction for one treatment. [6]

93% of people experienced “complete pain relief” from canker sores “immediately” after light treatments in a 2014 study. [7]

75% of patients reported less pain after only one light therapy treatment in a 2010 study in Brazil. [8]

A 2009 study reported that light therapy treatments “immediately and dramatically” reduced pain in patients with recurrent canker sores, “with no visible side effects.” [9]

Numerous other studies have been conducted on light therapy and canker sores and found similar results: light therapy reduces pain from canker sores to a significant degree compared to placebo or other treatments. [5,10,11,15]

Faster Healing Times for Canker Sores With Light Therapy

Using light therapy may improve healing times for canker sores by as much as a week. A 2014 study looked at whether light therapy treatments could speed up the healing time of canker sores. Researchers divided patients into a light therapy group and a placebo control group. The findings showed significant improvements in the light therapy group. Patients using light therapy healed from their canker sores in 2-4 days. Patients who didn’t use light therapy healed in 7-11 days. This study’s results showed that light therapy can speed up the healing of canker sores by a full week. [7]

Other studies around the world have found similar results. A 2012 trial reported that “the healing period was significantly shorter in ulcers treated by [light],” adding that the process “was not painful.” [12] Across studies, light therapy treatments have been well-tolerated by people with canker sores, and shown significantly faster healing times.

Light Therapy for Recurrent Canker Sores

A systematic review of studies conducted in 2016 examined whether light treatments are effective against recurrent canker sores. Compared to placebo or medical treatments, the authors found light therapy is “superior in relieving ulcer pain and shortening healing time.” [13]

Improved Eating and Drinking With Canker Sores

Light therapy has also shown promise for helping recurrent canker sore (RAS) patients live more normal lives as they go through outbreaks. A Swedish study in 2014 found light therapy treatments “relieved the difficulty of drinking, eating, and brushing teeth.” [11]

Healing Stress-Related Canker Sores and Immune-Related Canker Sores

Many people report getting canker sores when they experience stress. Others may get canker sores because of immune deficiencies and conditions. A 2004 Israeli study is one of the few to examine light therapy for stress and immune-related canker sores. Data showed that patients stress-related and immune-related canker sores reported “immediate pain relief” with light therapy treatments. [15]

Conclusion: Canker Sores and Light Therapy

Canker sores are painful, recurrent oral ulcers that are treated with a wide range of at-home and medical remedies. Clinical research is showing that light therapy treatments can have a significant impact on the healing course of canker sores, both by lessening pain and speeding healing time. Crucially, light therapy treatments have been well-tolerated by patients with canker sores. As light therapy becomes more widely adopted for oral health, it will be important to conduct more clinical trials to better standardize treatment parameters for specific conditions like canker sores. [14] Many such trials are underway, and the future of canker sore relief with light therapy looks bright.


Sources and References:

[1] The American Academy of Oral Medicine. Canker Sores.

[2] The Cleveland Clinic. Canker Sores.

[3] Understanding Canker Sores.

[4] Soliman HA, Mostafaa D. Clinical Evaluation of 660 nm Diode Laser Therapy on the Pain, Size and Functional Disorders of Recurrent Aphthous Stomatitis. Open Access Maced J Med Sci. 2019 May 14;7(9):1516-1522.

[5] Jijin MJ, Rakaraddi M, Pai J, Jaishankar HP, Krupashankar R, Kavitha AP, Anjana R, Shobha R. Low-level laser therapy versus 5% amlexanox: a comparison of treatment effects in a cohort of patients with minor aphthous ulcers. Oral Surg Oral Med Oral Pathol Oral Radiol. 2016 Mar;121(3):269-73.

[6] Prasad R S, Pai A. Assessment of immediate pain relief with laser treatment in recurrent aphthous stomatitis. Oral Surg Oral Med Oral Pathol Oral Radiol. 2013 Aug;116(2):189-93. doi: 10.1016/j.oooo.2013.02.011. Epub 2013 Apr 23. PMID: 23622766.

[7] Aggarwal H, Singh MP, Nahar P, Mathur H, Gv S. Efficacy of low-level laser therapy in treatment of recurrent aphthous ulcers – a sham controlled, split mouth follow up study. J Clin Diagn Res. 2014 Feb;8(2):218-21.

[8] De Souza TO, Martins MA, Bussadori SK, Fernandes KP, Tanji EY, Mesquita-Ferrari RA, Martins MD. Clinical evaluation of low-level laser treatment for recurring aphthous stomatitis. Photomed Laser Surg. 2010 Oct;28 Suppl 2:S85-8. doi: 10.1089/pho.2009.2661. PMID: 20950190.

[9] Zand N, Ataie-Fashtami L, Djavid GE, Fateh M, Alinaghizadeh MR, Fatemi SM, Arbabi-Kalati F. Relieving pain in minor aphthous stomatitis by a single session of non-thermal carbon dioxide laser irradiation. Lasers Med Sci. 2009 Jul;24(4):515-20.

[10] Huo X, Han N, Liu L. Effect of different treatments on recurrent aphthous stomatitis: laser versus medication. Lasers Med Sci. 2020 Nov 2.

[11] Albrektson M, Hedström L, Bergh H. Recurrent aphthous stomatitis and pain management with low-level laser therapy: a randomized controlled trial. Oral Surg Oral Med Oral Pathol Oral Radiol. 2014 May;117(5):590-594.

[12] Zand N, Fateh M, Ataie-Fashtami L, Djavid GE, Fatemi SM, Shirkavand A. Promoting wound healing in minor recurrent aphthous stomatitis by non-thermal, non-ablative CO(2) laser therapy: a pilot study. Photomed Laser Surg. 2012 Dec;30(12):719-23.

[13] Han M, Fang H, Li QL, Cao Y, Xia R, Zhang ZH. Effectiveness of Laser Therapy in the Management of Recurrent Aphthous Stomatitis: A Systematic Review. Scientifica (Cairo). 2016;2016:9062430.

[14] Amorim Dos Santos J, Normando AGC, de Toledo IP, Melo G, De Luca Canto G, Santos-Silva AR, Guerra ENS. Laser therapy for recurrent aphthous stomatitis: an overview. Clin Oral Investig. 2020 Jan;24(1):37-45.[15] Sharon-Buller A, Sela M. CO2-laser treatment of ulcerative lesions. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2004 Mar;97(3):332-4.


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