Mouth ulcer

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at October 27, 2016
StartDiseasesMouth ulcer

Mouth ulcers are a usually benign and irritating condition where one or more sores appears inside the mouth. These sores typically last for a week or two and they make eating difficult because contact with them is painful. Sometimes, a mouth ulcer is an indicator of a more serious condition and it is advised that a doctor be consulted if an ulcer lasts more than three weeks.


Definition & Facts

Mouth ulcers are circular, swollen sores that appear inside the mouth on the cheeks, lips, or the tongue. These sores vary in color from white to red. Some people get more than one at a time, and they can spread or expand.

There are a number of different types of mouth ulcers. Cold sores are a form of type 1 herpes and are quite contagious. They begin as blisters and then slowly harden. The herpes virus can lay dormant for years and then be activated by stress, hormones or a fever.

Aphthous ulcers are also known as canker sores. Minor aphthous ulcers are the least painful and the most common. Up to five can appear at one time, they are yellow in appearance and they will last about a week. Major aphthous ulcers are quite rare and will usually be larger than 10 millimeters. They can last up to a few months and can make eating difficult. Herpetiform ulcers are even more rare. They are the size of the head of a pin and will last a month or two. 

Symptoms & Complaints

Mouth ulcers can hurt quite a bit especially when eating, drinking or brushing teeth. Accidentally biting one can be extremely painful and in general the more it is interacted with, the worse it gets. They will sometimes pulse or throb in a painful way and are sensitive to most foods and drinks.

Ulcers on the inside of the lip can be quite unsightly and noticeable when they get large enough. The ulcer will be round and might be white or yellow. They are often red and inflamed around the sides.

Some people find that the ulcer reacts negatively to hot drinks or food. Mouth ulcers on the lip can give the lip a swollen, bulging appearance which can cause people to feel self-conscious. It is advised to go see a doctor if the ulcer lasts more than a few weeks, if more mouth ulcers appear, or the mouth becomes more red. That could be an indicator of a bacterial infection which will need to be treated with antibiotics.


The most common cause of a mouth ulcer is when a person accidentally bites their cheek or tongue. These are known as "traumatic" ulcers. Cold sores are caused by the herpes virus, which can be a sexually transmitted disease.

Mouth ulcers are sometimes caused by medications certain non-steroidal anti-inflammatory drugs (NSAID's) such as ibuprofen. Nicorandil, which is used to treat angina, is linked to mouth ulcers. Beta blockers used to control blood pressure is a cause, as is chemotherapy.

When ulcers form because of chemo, it is part of a condition called mucositis. Sometimes ulcers are caused by dentures that do not fit properly. Some women find that they get ulcers just before they have their period and in some cases, women don't start getting them until after menopause.

Occasionally, a person who quits smoking will start developing mouth ulcers. A lack of iron or vitamin B12 deficiency can lead to ulcers, as can stress and anxiety. Certain illegal substances can cause mouth ulcers, including cocaine. People who have Crohn's disease, celiac disease and HIV are more prone to having mouth ulcers.

Diagnosis & Tests

A mouth ulcer is something that is pretty simple to diagnose. The patient will feel it and they will be able to see it in the mirror. Doctors should be consulted in some cases because certain types of ulcers are more serious than others. The doctor should be told if there are symptoms appearing in addition to the mouth ulcers. These symptoms might include skin ulcers or joint pain and muscle pain. In those cases, the doctor will likely order a blood test.

Oral cancer can sometimes start as a mouth ulcer, so it is recommended that anyone who has a mouth ulcer that remains for three weeks or more should see a doctor or dentist, particularly if the person smokes. The doctor might refer the patient to a specialist who will do a biopsy of the ulcer and test it to see if it is cancerous.

Other conditions will need to be ruled out. Candidiasis, also known as "thrush," will appear as white spots in the mouth. It will be accompanied with a sore throat and cracking at the center of the mouth. Thrush is a fungal infection entirely separate from mouth ulcers.

Treatment & Therapy

Mouth ulcers aren't always treated. They usually go away on their own after a week or two. There are ways to reduce the swelling and to ease the pain. That could help prevent more ulcers from forming or make consuming meals less painful. Pharmacists can prescribe a special kind of toothpaste the can speed up healing. Those with ulcers should use toothbrushes with soft bristles and avoid toothpaste that has sodium lauryl sulphate. It is recommended to avoid food that is spicy, hot or contains a lot of salt.

Using a straw for drinks is helpful and anything that causes pain should be avoided as much as possible. Mouthwash should be used, as it prevents infection and can speed up the recovery process. Some doctors can prescribe painkillers in the form of gel, lozenges or a spray. They might sting a little and cause the mouth to feel numb. Corticosteroid lozenges can ease the pain and aid the healing the process as well. 

Prevention & Prophylaxis

There is only so much a person can do to prevent mouth ulcers because some causes are genetic or related to a medical condition. It helps to avoid chocolate, coffee, cheese and wheat flour if one is having mouth ulcers. Gum should be avoided. Practicing yoga and meditation can reduce stress levels and lower the occurrence of mouth ulcers.