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Canker sores (aphthous ulcers) appear as small, painful swellings on the lips or inside the mouth. The painful sores are covered by a mixture of fluids, white blood cells, and bacteria. They typically have a white, gray, or yellowish film with a red border.
In the beginning stages, the sores may appear as small red dots. In some cases, they can be as large as a quarter. As a canker sore is forming, it is not uncommon to feel irritation, tingling, and burning sensations around the infected area.
Canker sores do not develop outside of the mouth. Rather, the sores can develop in a few different areas in and around the mouth, including:
Canker sores can also develop on or under the tongue. These sores are typically caused by mouth injuries, braces, dental work, sports accidents, or brushing your teeth too hard.
There are three types of canker sores, including minor sores, major sores, and herpetiform sores. They are distinguished by their size, shape, and pain level:
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Minor canker sores are the most common type, affecting more than 80 percent of sore sufferers. Characteristics of minor canker sores:
Major canker sores are more severe and appear less commonly than minor canker sores. Characteristics of major canker sores:
Herpetiform sores are the least common type of canker sore. Characteristics include:
Canker sores are not cold sores. They are noncontagious inflammations, rather than infections.
The herpes simplex virus type 1 (HSV-1) is a highly contagious infection that causes cold sores (fever blisters). Cold sores are small, fluid-filled blisters that usually appear on the hard part of the gums or the outside of the lips. HSV-1 spreads through close personal contact, such as kissing, hugging, handshakes, sharing drinks, and sharing utensils. Herpes is a lifelong disease with no cure.
Canker sores are not contagious. You cannot get a canker sore by sharing food, utensils, drinks, or kissing an individual who has a canker sore.
A cold sore (HSV-1) is contagious if an oozing blister is present. However, the sore is not contagious if it has completely scabbed.
The cause of a canker sore is difficult to pinpoint, but it could be linked to food allergies, acidic conditions, oral health habits, or even a small cut. Women are also more likely to develop canker sores, but the reason why is unknown. Common risk factors include:
Brushing twice a day, flossing at least once a day, and rinsing the mouth regularly kills bacteria and keeps the mouth healthy. To avoid them, it is also important to limit hard, crunchy, unhealthy, or irritating foods (acidic).
Canker sores may develop after having dental work done. Sports injuries, brushing the teeth excessively, small cuts, and accidental cheek biting can also cause them.
Acidic foods, spicy foods, coffee, strawberries, eggs, nuts, eggplants, cheese, tomatoes, and gluten may cause allergic reactions in some people. These reactions can lead to the formation of canker sores.
Toothpaste containing sodium lauryl sulfate (SLS) can cause canker sores. The ingredient is known to irritate the tissues inside the mouth and gums. If ulcers are recurrent, toothpaste is likely the culprit.
Excessive intake of sugar, processed foods, and citrus fruits can cause aphthous ulcers. It is recommended to eat salads with raw onions because they contain sulfur, which has antibacterial effects.
Puberty, menopause, and menstrual cycles can increase inflammation in and around the mouth.
Canker sores are not a symptom of HIV (human immunodeficiency virus), which is a virus that breaks down cells in the immune system. Although, people with HIV/AIDS may develop severe sores more frequently than those without the virus.
Emotional or physical stress can cause canker sores in some people because excessive stress increases inflammation.
Frequent canker sores are associated with certain diseases and chronic health conditions. These health conditions include, but are not limited to:
To avoid canker sores, the body needs a proper balance of acidity, minerals, and alkalinity. Iron, zinc, vitamin B12, and folic acid deficiencies have been linked to canker sores. Calcium deficiencies also cause canker sores and can even make the sores worse.
Tests are not needed to diagnose a canker sore. Your dentist or doctor may recommend blood work if the ulcer(s) does not disappear on its own or there is a severe breakout present. You may also benefit from a vitamin deficiency test if you experience frequent sores.
Minor canker sores typically go away on their own within a week. Although, if major canker sores develop, it is important to seek treatment. Over-the-counter products are usually recommended, including:
Canker sores usually disappear on their own within 7 to 10 days. There are a few natural home remedies that can be used to help speed up the healing process and decrease irritation. Natural remedies for fast canker sore relief include:
In most cases, canker sores are a natural part of life. However, if you develop sores frequently, there are ways to prevent them from developing. Prevention tips include:
Canker sores normally do not have any complications or risks if they are caused by natural factors. In rare cases, canker sores can be an early sign of oral cancer (mouth cancer). Ulcers caused by oral cancer are typically painful, thicken over time, and do not disappear on their own.
Balch, Phyllis A. Prescription for Nutritional Healing. Avery, a Member of Penguin Group (USA) Inc., 2010.
Zand, Janet, et al. Smart Medicine for a Healthier Child: a Practical A-to-Z Reference to Natural and Conventional Treatments for Infants and Children. Avery, 2004.