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Oral Ulcer: Causes, Home Remedies, & When to See a Doctor

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Last updated March 10, 2021

Oral ulcer questionnaire

Use our free symptom checker to find out what's causing your oral ulcer.

Understand your oral ulcer symptoms with Buoy, including 9 causes and common questions concerning your oral ulcer.

Oral ulcer questionnaire

Use our free symptom checker to find out what's causing your oral ulcer.

Oral ulcer symptom checker

Oral ulcer symptoms

One day everything in your mouth was fine, the next you've got a sore that just won't stop yelling for attention. They can be painful, unsightly, and disturbing. They can feature themselves prominently on your lips and ruin your complexion. An ulcer of the mouth is certainly quite the bother, especially when you have no idea how it got there.

An ulcer is a discontinuity of a surface lining. Oral ulcers include aphthous ulcers which are painful oral ulcers with a grayish base and also known as canker sores. An oral ulcer is an open sore located inside your mouth. Anything that damages the surface layers of the tissues in your mouth can cause an ulcer, whether that be a viral infection, inflammation, or some sort of damaging exposure. Luckily, the mouth tends to heal quite quickly, so most ulcers don't last that long. But while the cause of an oral ulcer isn't always clear, one thing is they are quite annoying.

Common accompanying symptoms of oral ulcers

Oral ulcers may be associated with these common symptoms:

  • Pain at the site of the ulcer
  • Swelling
  • Pus and other discharge
  • Sore throat
  • Avoidance of certain acidic foods or drinks

Causes of an oral ulcer

Infections may lead to oral ulcers.

Inflammatory causes

Your body's immune system may behave abnormally and attack your own tissues if you have an autoimmune disease. Examples include lupus and Behet's disease and Crohn's disease.

Cancer causes

Cancers and "pre-cancers" of the mouth may manifest as oral ulcers or discoloration.

Environmental causes

Environmental causes may be related to certain exposures or habits.

  • Nutritional deficiency: Your body needs many nutrients to maintain its tissues. Deficiencies of some types of nutrients such as folate and vitamin B12 can lead to oral ulcers.
  • Medications: Oral ulcers are an uncommon but serious reaction to some medications.
  • Chemical exposure: Chemicals can burn your mouth and cause oral ulcers.
  • Burns: Eating or drinking something that is too hot can lead to thermal burns and resultant oral ulcers.
  • Trauma: Accidentally biting your lip or chewing something sharp can damage the surface lining of your mouth.

This list does not constitute medical advice and may not accurately represent what you have.

Canker sore

Canker sores are small, grayish-white sores in the mouth, often on the inside of the cheeks, lips, and on the tongue. No one really knows why canker sores happen, but it seems to be inherited and susceptible to vitamin deficiencies and allergies.

Rarity: Common

Top Symptoms: painful mouth sore, numerous mouth sores, mouth sore surrounded by a red area, single mouth sore, oral ulcer

Symptoms that always occur with canker sore: painful mouth sore

Urgency: Self-treatment

Oral ulcer questionnaire

Use our free symptom checker to find out what's causing your oral ulcer.

Oral ulcer symptom checker

Oral herpes

Herpetic stomatitis is a viral infection of the mouth that causes fever and red and inflamed gums. This typically happens early in childhood.

Rarity: Rare

Top Symptoms: fever, gum pain, painful mouth sore, gum swelling, gum redness

Symptoms that always occur with oral herpes: gum pain

Urgency: Self-treatment

Oral thrush

Oral thrush is the result of the overgrowth of the fungal species candida in the mouth. This fungus normally exists within the mouth and the rest of the GI tract as well as on the skin. Oral thrush can develop when larger amounts of the fungus are present than normal. The characteristic finding of oral .

Hand-foot-and-mouth disease

Hand-foot-and-mouth disease is caused by different types of enteroviruses. There is no connection to hoof-and-mouth disease, which only affects livestock.

Hand-foot-and-mouth disease is very contagious. The virus is carried in the secretions of the nose, mouth, rash blisters, and feces of an infected person.

Anyone coming into contact these substances, even through the air, can contract the disease.

Most susceptible are children under age 5, though the disease can occur in older children and adults.

Symptoms include sores and blisters inside the mouth; reddened, blistering skin rash on palms of hands and soles of feet; loss of appetite and dehydration due to difficulty with eating and drinking; and fever.

Diagnosis is made through physical examination and sometimes testing of throat swab or stool sample.

Treatment involves supportive care with fluids, rest, and mild pain relievers. Do not give aspirin to children. Antibiotics only work against bacteria and cannot help against a viral illness.

There is no vaccine against hand-foot-and-mouth disease. Frequent and thorough handwashing is the best way to prevent the spread of the illness.

Rarity: Rare

Top Symptoms: loss of appetite, cough, fever, new headache, sore throat

Symptoms that always occur with hand-foot-and-mouth disease: spontaneous skin changes

Urgency: Self-treatment

New onset crohn's disease

Crohn's disease is an inflammation of the bowel. It is caused by a faulty immune system response which makes the body attack the lining of the intestines.

The disease usually appears before age thirty and can affect anyone. Those with a family history may be most susceptible. Smoking is a known risk factor.

Aggravating factors include stress, poor diet, and nonsteroidal anti-inflammatory drugs such as ibuprofen and aspirin.

Early symptoms usually develop gradually, but can appear suddenly. These include fatigue, loss of appetite, fever, mouth sores, diarrhea, abdominal pain, and blood in stool.

Untreated Crohn's disease can cause ulcers throughout the digestive tract as well as bowel obstruction, malnutrition, and deteriorating general health.

Diagnosis is made through blood test and stool sample test. Colonoscopy, CT scan, MRI, endoscopy, and/or enteroscopy may also be used.

Crohn's disease cannot be cured, but can be managed through reducing the inflammation. Antibiotics, corticosteroids, and immune system suppressors may be tried. Excellent nutrition, vitamin supplements, smoking cessation, and reduction in stress can be helpful.

Rarity: Rare

Top Symptoms: fatigue, stomach bloating, loss of appetite, constipation, abdominal cramps (stomach cramps)

Urgency: Primary care doctor

Wegener's granulomatosis

Wegener's granulomatosis, more recently re-named granulomatosis with polyangiitis, is a disorder in which a dysregulated immune system causes widespread inflammation of small blood vessels throughout the body. This results in slower or impaired blood flow to your nose, sinuses, throat, lungs, and kidneys.

Symptoms can be widespread and affect various parts of the body such as the eyes and ears or respiratory system, yet usually begin more generally with fever, fatigue, a loss of appetite, and weight loss. With treatment, a full recovery is possible; however, this condition can be fatal.

Treatments include immunosuppressive medications in order to control the disease in the short- and long-term.

Rarity: Ultra rare

Top Symptoms: fatigue, loss of appetite, joint pain, shortness of breath, fever

Urgency: Primary care doctor

Blistering disease (pemphigus)

Pemphigus is an autoimmune disorder, meaning that the immune system attacks healthy cells in the skin and mouth, causing blisters and sores. This is a rare disease, and doctors are not completely sure of the cause.

Rarity: Ultra rare

Top Symptoms: nasal ulcer, skin peeling, hoarse voice, painful rash, red or pink, rough patch of skin

Urgency: Primary care doctor

Laryngeal cancer

Laryngeal cancer typically develops from the cells of the topmost layer of the vocal cord area. It can be caused by using tobacco products or drinking excessively.

Rarity: Rare

Top Symptoms: shortness of breath, unintentional weight loss, hoarse voice, trouble swallowing, pain with swallowing

Urgency: Primary care doctor

Mouth and throat sores from cancer treatment

Mouth sores are a common side effect of cancer treatment (chemotherapy or radiation therapy). Some types of chemotherapy are more likely to cause this than others. Cancer treatments are used to kill the bad cancerous cells, but unfortunately they also affect healthy cells. The cells of the inner lining of your mouth, esophagus (the tube that carries food from the mouth to stomach) and stomach can get damaged too. This can result in symptoms like red areas or a burning feeling in the mouth, painful sores and painful or difficulty swallowing.

Rarity: Rare

Top Symptoms:

Urgency: Primary care doctor

Oral ulcer questionnaire

Use our free symptom checker to find out what's causing your oral ulcer.

Oral ulcer symptom checker

Oral ulcer treatments and relief

Oral ulcers are, for the most part, a fact of life. You are bound to get one at some point and typically they go away after a few days because your mouth heals quite quickly. However, severe or recurrent ulcers may be indicative of any underlying disease process and should be investigated by a healthcare professional.

At-home oral ulcer treatments

The following at-home remedies may provide relief from some of your symptoms.

  • Avoid irritating foods: Certain foods and drinks, especially hot, spicy, or acidic ones, can irritate the oral ulcer and cause pain.
  • Ice: Ice can dull the pain and swelling associated with some ulcers, especially those caused by biting the lip.
  • Over-the-counter topical analgesics: Certain pain medications can be applied directly to the site of the ulcer and dull the pain or protect the site from further damage.
  • Oral hygiene: Keep brushing your teeth and use an antiseptic mouthwash to cut down on the risk of infection and hasten healing of the ulcer.
  • Watch and wait: Most ulcers come and go on their own time and will improve as the mouth does its best to heal the area.

Medical oral ulcer treatments

You should consult your physician if at-home treatments do not provide relief or your oral ulcers worsen. He or she may complete/recommend the following.

  • Oral exam: Your doctor will likely perform an extensive oral exam.
  • Laboratory testing: Your doctor may perform blood tests or swabs of the ulcer to figure out what is causing it.
  • Medications: Some causes of ulcers will respond to medications. This is typical of many infections and autoimmune diseases.
  • Surgery: Rarely, oral ulcers are a symptom or manifestation of a disease requiring surgery, such as cancer of the mouth.

When oral ulcers are an emergency

You should seek help without delay if you have:

Questions your doctor may ask about oral ulcer

  • Have you ever taken a course of antibiotics in your life?
  • Do you feel fullness or pressure in your face?
  • Do you feel pain when you swallow?
  • What color is the area right around your sore/blister/bump?
Share your story
Dr. Rothschild has been a faculty member at Brigham and Women’s Hospital where he is an Associate Professor of Medicine at Harvard Medical School. He currently practices as a hospitalist at Newton Wellesley Hospital. In 1978, Dr. Rothschild received his MD at the Medical College of Wisconsin and trained in internal medicine followed by a fellowship in critical care medicine. He also received an MP...
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