Mouth Ulcer / Herpitiform Aphthous Ulcer of the palate, Photo by Dr. Khalifeh

If you feel irritation or pain in a particular region of your mouth, it may be because of mouth ulcers or sores. Mouth ulcer or mouth sores are areas in the oral cavity that appear as cuts or ulcers and can be unsightly, painful, and annoying. The good news is that most of the mouth ulcers and sores are harmless and self-healing. This article explains everything you need to know about mouth ulcer and sores, their types, symptoms, causes, prevention, treatment and cure.

What are the Causes of Mouth Ulcer?

According to the American Dental Association, mouth ulcer can be caused due to various reasons. However, some of the main reasons include:

  • Infections – any type of infection, whether bacterial, fungal, or viral, can cause mouth sores.
  • Irritation and Trauma – frequent irritation of the oral soft tissues and the tongue, caused by loose orthodontic wire, a sharp edge of a filling, or a denture can cause ulcers. These types of ulcers typically develop on the soft tissues that lie opposite to damaged restoration or prosthesis.
  • Allergic reaction – sensitivity or allergy to certain foods, various ingredients found in toothpaste and other dental hygiene products can also lead to a mouth ulcers and sore mouth.
  • Systemic Disease – oral ulcers can also develop due to underlying medical conditions. Examples of these conditions include autoimmune conditions, gastric problems, pregnancy, hormonal changes, and renal issues.
    Medications and Cancer Treatment – certain drugs, radiation therapy and chemotherapy for oral cancer and other cancers can also result in mouth ulcer and sores.
  • Stress – people often experience mouth sore formation during stressful periods, such as examinations or competitions.

What are the Types of Mouth Ulcer (Sores)?

Some of the common types of mouth ulcers include:

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Canker Sores / Canker Ulcer

Cold Sore of the Soft plate. Photo by Dr. Khalifeh

Also known as the aphthous ulcer, these are non-contagious, small, oval, or round, yellowish lesions. Thes ulcers develop on the softer, movable parts of the mouth such as the tongue, cheeks, and the soft palate. According to the American Academy of Oral Medicine, these mouth ulcers are the most common oral conditions experienced by half of the American population. There are three types of canker ulcers (Canker sores):

Minor Aphthous Ulcer – are the most common form of canker sores. They are small (less than 1cm diameter), and they usually heal by themselves in 2 week without scarring.

Major Aphthous Ulcer – these ulcers are less common than minor aphthous ulcer but are more severe. These are over 1cm in diameter and often take two weeks or more for healing. They may also be extremely painful in some cases and may leave scars.

Herpetiform Ulcer – these are the least common aphthous ulcer that are very small in size and often clump together to become larger. Herpetiform ulcers usually heal within one week.

Cold Sores

Cold Sore, Photo taken by Dr. Khalifeh

According to the American Dental Association, cold sores are groups of fluid-filled, painful blisters. They typically appear on the lips and occasionally around the skin of the lips. Also known as fever blisters. These mouth sores are caused by a herpes viral infection. Although these ulcers typically heal in 2 weeks, they often leave behind an unsightly scab after healing. Your dentist may prescribe painkillers to relieve the discomfort. Antiviral treatment may be needed if the infection recurs frequently. This form of mouth sores are usually contagious. Once a person gets infected with primary herpes, the virus stays inside the body and may cause secondary infection at any time.


Leukoplakia of the side of the tongue. Photo by Dr. Khalifeh

This is a white or greyish patch that can develop anywhere inside the oral cavity. These patches often form as a result of chronic irritation. Possibly caused by ingestion of certain foods, cheek biting, improper dental restorations or prostheses, and smoking. Leukoplakia generally develops slowly and does not cause pain or sensitivity. While these are mostly harmless, they can sometimes become cancerous.


These are red patches that can develop anywhere in the oral cavity. Commonly found on the floor of the mouth, sides of the tongue, or on the gum tissue behind the back teeth. Although less common than leukoplakia, these red lesions are potentially cancerous. If these ulcers do not heal within two weeks, you should immediately consult your dentist for a biopsy.


Candida Infection of the plate. Photo by Dr. Khalifeh

According to the Centers for Disease Control and Prevention (CDC), candidiasis is caused by a fungal infection. Candidiasis appears in the form of creamy red or white patches inside the oral and other body cavities. Also known as oral thrush, these lesions can be caused due to various reasons. Possible causes include prolonged wearing of unclean dentures, decreased body immunity, and diabetes. Prolong use of antibiotics can cause fungal infection in the mouth and genetal areas. Apart from red or white patches, oral thrush may also cause bad breath and create difficulty in eating and swallowing.

Mouth Ulcer Associated with Autoimmune conditions

Mouth Ulcer / Pemphigus Vulgaris of the Gingiva, Photo by Dr. Khalifeh

These ulcers are usually chronis and harder to treat. Among these conditions are: Pemphigus Vulgaris, Mucous Membrane Pemphigoid, Lichen Planus, Crohn’s disease.

Oral Cancer

Squamous Cell Carcinoma of the Tongue, Photo by Dr. Khalifeh

Mouth ulcers that are mostly painless that exist for more than 2 weeks for no apparent cause could be cancerous lesions. Most common locations for oral cancer are the side of the tongue, under the tongue and the lower lip. If you find an ulcer in these areas that didn’t heal in 2 weeks, consult with your dentist immediately. The size of the mouth ulcer in this case does not matter.

What is the Treatment for Mouth Ulcer and Mouth Sores?

Most mouth ulcers are harmless, and they heal by themselves. However, if any swelling or lesion persists beyond two weeks, you must immediately contact your dentist or physician. Typically, the management of oral ulcers involves symptomatic treatment to reduce pain and discomfort.

How to Get Rid of Mouth Ulcer?

Apart from this, the American Dental Association recommends the following to get red of mouth ulcers: 

  • Avoiding hot drinks that can cause further discomfort
  • Avoid alcohol and fizzy beverages
  • Maintain optimal oral hygiene
  • Discontinue any oral hygiene product that causes further sensitivity
  • Take soft diet
  • Laser treatment proved to be effective for certain forms of mouth ulcers.

Dr. Khalifeh may also prescribe painkillers in some cases to reduce inflammation and pain. Some mouth ulcers may require steroid therapy to manage painful symptoms.
In rare cases, oral lesions can turn into cancerous lesions. Since the incidence of oral cancer is increasing each year, Dr. Khalifeh routinely screen each patient for oral cancer during regular checkup appointments. If he finds any suspicious or non healing lesion, Dr. Khalifeh will perform an oral biopsy to confirm the diagnosis. That is another reason why you should visit your dentist regularly for checkups. Although oral cancer is a deadly disease, it is almost completely treatable if diagnosed early.

When I should Be Concerned About Mouth Ulcer?

The appearance of oral ulcers is one thing to be worried about. However, if the ulcer or sore frequently appears or does not heal, then it is cause for concern. Remember, whenever in doubt, it is always better to seek professional help than wait. A lesion that you consider harmless might be a cancerous lesion in its early stages. So, don’t forget to visit your dentist regularly for checkups, not just to enjoy a fresh breath and beautiful smile, but also to protect yourself from dental problems.

How to Prevent Mouth Ulcer and Mouth Sores?

Mouth ulcers can only be prevented if we know the cause for the mouth ulcer you have. Some of the mouth sores can be avoided and some cannot. Oral cancer can be prevented by avoiding smoking, alcohol and vaccinating for HPV infection.

Canker sores may be avoided by stress reduction, avoiding using products you are allergic to and maintaining good oral hygiene.

Avoiding prolonged use of antibiotics and keeping your dentures clean may help protect you from getting fungal infection.

Who I Should See for Mouth Sores in Los Angeles?

Los Angeles patients suffering from mouth ulcer or mouth sore should contact our Los Angeles dental center for best treatment.

Dr. Khalifeh is a specialized dentist serving patients in Los Angeles, Beverly Hills, Miracle Mile, 5757 Wilshire Blvd., Hollywood, Larchmont Village and all regions in southern California. He hold a master of science degree in Orofacial Pain and Oral Medicine from the University of Southern California. He is an expert in recognizing and treating various forms of mouth ulcer conditions, mouth sores and other oral lesions.

Pictures of Mouth Ulcer and Mouth Sores

Herpitiform Aphthous of the palate, Photo by Dr. Khalifeh
Herpitiform Aphthous Ulcer of the palate, Photo by Dr. Khalifeh
Traumatic Ulcer of the tongue, Photo by Dr. Khalifeh
Allergic reaction to viral infection
Oral Ulcer / Mucous Membrane Pemphigoid of the Cheek, Photo by Dr. Khalifeh
Oral Ulcer / Pemphigus Vulgaris of the Gingiva, Photo by Dr. Khalifeh
Planes of the Tongue, Photo by Dr. Khalifeh
Oral Lichen Planes of the Tongue, Photo by Dr. Khalifeh
Oral Candidiasis of the Tongue, Photo by Dr. Khalifeh
Oral Ulcer / Cancer at the Floor of the Mouth, Photo by Dr. Khalifeh
Squamous Cell Carcinoma of the side of the tongue, Photo by Dr. Khalifeh
Hyper-keratotic Candida infection of the tongue, Photo by Dr. Khalifeh
Traumatic ulcer of the lower lip. Photo by Dr. Khalifeh
Candida infection (Thrush) and geographic tongue, Photo by Dr. Khalifeh
Tongue ulcers caused by Behcet's Disease. Photo by Dr. Khalifeh
Lingual Papillitis, Photo by Dr. Khalifeh
Traumatic ulcer of the tongue border. Photo by Dr. Khalifeh
Traumatic ulcer of the hard palate. Photo by Dr. Khalifeh

9 thoughts on “Mouth Ulcer”

  1. It is very distressing to see so many people these days who aren’t developed that much aware of this. So we need to know more about this disease. Your article is very informative and it has very clear concept about Ulcer symptoms that is very effective for everyone who has no idea about its consequence. Best of luck.

  2. I have a chronic non-traumatic tongue ulcer that I’ve had for 30 plus years. I’m desperate to get help. It’s been removed multiple times but keeps coming back. It’s extremely itchy and painful. I can’t seem to find answers anywhere.

  3. Mine is critical. I have been even dropping weight a lot with a lot of injuries in my mouth and it comes and goes. Sometimes I get Uvulitis and I still has gastritis.

  4. Hi,

    I have these on the roof my mouth almost constantly. I also suffer from severe stomach issues which no one can find answers to but everyone I’ve seen regarding these sores say they are related to my stomach issues. I can’t seem to find any answers anywhere!

  5. Hi,

    I have these almost constantly and I also suffer from chronic abdominal pain and stomach issues. I’ve been told several times that both of these symptoms are connected but I’ve had 18months of no answers! It’s so frustrating.

  6. I have a B12 deficiency and I thought my mouth ulcers were caused by that but they aren’t healing I get some of my sides of my tongue that usually go away but there’s one on the inside of my left cheek that won’t go away and it seems to be spreading a little bit it’s been there for months I want to say maybe more than 6 months I’m getting kind of scared now

    1. Sorry that you are suffering. If you are in Los Angeles or close to Los Angeles, I will be happy to help. You may find a dentist specializing in Oral medicine to consult with him.

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