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Canker sores (aphthous ulcers) are small, shallow, and painful lesions that develop on the lips or inside the mouth. They appear as small round lesions with a white center (scientifically known as “slough”) and a red border (inflamed tissue).
The sores are a mixture of fluids, white blood cells, and bacteria. In some cases, canker sores can be as large as a quarter.
Canker sores don't form outside of the mouth. Instead, they form in the following areas:
Common causes of canker sores include:
Poor oral hygiene allows bacteria to develop in the mouth. Maintaining good oral hygiene prevents this from happening.
Keeping the mouth healthy includes:
Limiting hard, crunchy, unhealthy, or irritating foods (acidic) is helpful in preventing canker sores.
Oral injuries have many causes. These include:
Sustaining an oral injury through any of these means can increase the risk of developing sores.3,5
Allergic reactions to food can cause the formation of canker sores.
These foods include:
Toothpaste containing sodium lauryl sulfate (SLS) can cause canker sores. SLS 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.
Some people recommend eating salads with raw onions because they contain sulfur, which has antibacterial effects.
Hormonal imbalances can increase inflammation in and around the mouth. Causes include:
People with HIV/AIDS may develop severe sores more frequently than those without the virus.
Canker sores aren’t a symptom of human immunodeficiency virus (HIV), which is a virus that breaks down cells in the immune system. Rather, it’s a side effect of immune system impairment.
Emotional or physical stress can cause canker sores in some people because excessive stress increases inflammation.
Frequent canker sores can occur with certain diseases and chronic health conditions.
These health conditions include, but aren’t limited to:
The body needs a proper balance of acidity, minerals, and alkalinity to avoid canker sores.
You may get canker sores if you're deficient in:3,4
medical symptom mouth dental ulcer canker sore
Close up of a girl with aphthous stomatitis in her lip
Regardless of your treatment, canker sores don’t disappear within 24 hours. However, there are ways to avoid prolonging the healing stage.
You can use over-the-counter drugs and mouth rinses like:
Doctors advise against popping canker sores. This can be extremely painful.
It's important to know that one possible side effect of tetracycline is a fungal infection called oral thrush. Ironically, oral thrush can lead to mouth sores.
Canker sores aren’t 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.
Cold sores spread through close personal contact. This includes:
Herpes is a lifelong disease with no cure.
During the formation of a canker sore, it isn’t uncommon to feel discomfort around the infection.
Symptoms that a canker sore is beginning to form include:
If you have a severe case of canker sores, you may experience other symptoms, which include:
You can use a few natural home remedies to help speed up the healing process and decrease irritation. These 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 are small, painful lesions that develop inside the mouth. They can be small or large and typically have a white, gray, yellow, or red border.
There are three types of canker sores. Each one can vary in size, discomfort, and healing duration:
Most canker sores go away on their own within a week. If they last longer than two weeks, seek treatment.
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