A guide to stomatitis and mouth pain: from aphthous sores to ulcers that will not heal

Stomatitis is the general term for inflammation of the lining of the mouth, such as the lips, tongue, gums, palate and inside of the cheeks, and it usually comes with pain. According to the National Health Information Portal of the Korea Disease Control and Prevention Agency (KDCA, 질병관리청), the most common type, aphthous stomatitis, heals within 10 to 14 days without scarring, but an ulcer that does not respond to 2 to 3 weeks of treatment needs a biopsy to rule out other diseases. By cause it divides into infectious and non-infectious types, so it is important to judge when to get care from the look and duration.

Published 2026-11-08 · Updated 2026-11-08 · DentalStatics editorial team

Key facts

Definition of stomatitis	A general term for inflammatory disease of the lining of the lips, tongue, gums, palate and inside of the cheeks (source: KDCA National Health Information Portal)
Infectious stomatitis	Herpetic stomatitis, hand-foot-and-mouth disease, oral candidiasis (source: KDCA National Health Information Portal)
Non-infectious stomatitis	Aphthous stomatitis, burning mouth syndrome, radiation mucositis (source: KDCA National Health Information Portal)
Share of aphthous stomatitis	About 20% of oral mucosal diseases, the most common (source: KDCA National Health Information Portal)
Recovery from aphthous stomatitis	Heals within 10 to 14 days without scarring (source: KDCA National Health Information Portal)
Recovery from herpetic stomatitis	Usually heals within 2 weeks without scarring (source: KDCA National Health Information Portal)
Ulcer that may need a biopsy	An ulcer that does not respond to 2 to 3 weeks of treatment (source: KDCA National Health Information Portal)
Criterion for telling apart oral cancer	A biopsy is recommended for an ulcer that does not go away after about 3 weeks (source: National Cancer Information Center, National Cancer Center)

What kind of condition is stomatitis?

Stomatitis is what people commonly describe as a mouth sore or a raw mouth. The National Health Information Portal explains stomatitis as a general term for inflammatory disease of the lining of the lips, tongue, gums, palate and inside of the cheeks, and advises that it is common and usually painful.

The look varies: a round hollowed-out ulcer, a small blister, a white film that peels off when rubbed, or a red raw area. The suspected cause differs with the look, so remembering how it looked at first, how many there were, the size and the date it began helps at the visit.

Stomatitis occurs at any age. The National Health Information Portal explains that stomatitis is mainly common in people in their 20s and 30s and in children aged 10 and under, and also increases at age 50 and over, with more women in this age group.

What types of stomatitis are there?

The National Health Information Portal divides stomatitis into infectious and non-infectious by cause. Seoul National University Hospital's medical information also includes lichen planus, mucous membrane pemphigoid and pemphigus among non-infectious stomatitis. The typical types that cause mouth pain are as follows.

Even for the same mouth pain, you can make some guess at the type depending on whether blisters come first, whether a white film covers it, or whether it looks normal on the surface. However, many look alike on the outside, so the final judgment is made by an exam.

Aphthous stomatitis: the most common, a round ulcer with a clear border and a yellow center
Herpetic stomatitis: small blisters appear in clusters and burst into ulcers
Oral candidiasis: white patches that rub off, common in infants and denture wearers
Oral lichen planus: white lines in a net-like pattern, or red raw areas that sting
Burning mouth syndrome: the tongue and mouth burn with pain though nothing looks wrong
Traumatic ulcer: a wound caused by biting the cheek or rubbing against a sharp tooth or prosthesis

Why does stomatitis happen?

The cause of aphthous stomatitis has not yet been clearly identified, and the National Health Information Portal explains that a family history is found in about one third of patients. Seoul National University Hospital's medical information names immune abnormalities, a shortage of iron, folate and vitamin B12, injuries from brushing or eating, stress and menstruation as related factors.

Infectious stomatitis is caused by viruses, bacteria and fungi. The herpes simplex virus hides in nerve ganglia in the body and is reactivated by stress and other triggers, while Candida increases when the environment in the mouth changes, such as with denture use, dry mouth, uncontrolled diabetes and long-term antibiotic use. The National Health Information Portal also describes radiation mucositis, which develops during radiation therapy to the head and neck, as a kind of stomatitis.

Medicines you take can also be a trigger. The National Health Information Portal names long-term use of broad-spectrum antibiotics and use of steroid inhalers as triggers of oral candidiasis, and explains that dry mouth caused by drugs or Sjogren's syndrome can lead to ulcers of the oral mucosa and candidiasis.

Can stomatitis be a sign of another disease?

Most stomatitis responds well to proper treatment, but some is connected to a disease of the whole body. The National Health Information Portal advises that blood tests are sometimes done to rule out systemic diseases such as anemia, leukemia, hemophilia and acquired immunodeficiency syndrome (AIDS), and that recurring stomatitis requires checking for a hidden underlying disease. Behcet's disease, which rarely causes large aphthous ulcers, can leave permanent mucosal damage.

Oral cancer can also look at first like a mouth wound that will not heal. The National Cancer Information Center of the National Cancer Center explains that because simple inflammation usually heals in 2 to 3 weeks, an ulcer that does not go away after about 3 weeks should have a biopsy. A white patch that cannot be wiped off or a red patch that stays also may be a precancerous lesion and needs to be checked.

How is stomatitis treated at the clinic?

Treatment combines treatment of the cause with symptomatic treatment that reduces pain. According to the National Health Information Portal, for aphthous stomatitis an anesthetic mouthwash, an antibacterial mouthwash, a topical steroid ointment and a mucosal protectant can be used, an antiviral for herpes, and an antifungal for oral candidiasis.

The same ointment may not suit every cause. The National Health Information Portal advises that hand-foot-and-mouth disease needs no special treatment but steroid ointment is best avoided. Which drug to use is safest decided after the cause is confirmed by an exam.

Seoul National University Hospital's medical information explains that starting drug treatment while an aphthous lesion is small helps shorten the time of illness, and that when pain is severe a topical anesthetic applied before meals can be used. If a large ulcer does not improve with topical treatment, an oral medicine is considered, but it may have side effects, so follow the instructions of the prescribing doctor.

How do I manage stomatitis at home?

The National Health Information Portal recommends adequate nutrition, oral hygiene, dental care, quitting smoking and drinking, and avoiding irritating foods as everyday care for stomatitis. Adding the lifestyle rules of Seoul National University Hospital's medical information gives the following summary.

When pain is severe, eating lukewarm, soft food in small portions irritates the ulcer less. A dry mouth damages the lining more easily, so as in the dry mouth guidance of the National Health Information Portal, it is good to moisten the mouth by drinking small amounts of water often.

Do not skip brushing, and brush the ulcer area gently with a soft toothbrush
Avoid spicy, salty and sour foods and hard snacks and nuts
Do not chew food while talking, so the cheek and tongue do not get bitten
Discuss supplementing vitamin B12, iron and folate that are lacking in the diet after an exam
Drink water often so the mouth does not dry out

When should I get care for stomatitis?

Mild stomatitis usually heals by itself, but in the cases below it is good to see a dentist or an ENT clinic. In particular, do not put off care if the ulcer lasts beyond the usual healing time or a firm lump can be felt in the same place.

At the visit, telling them the date the ulcer began, the medicines used so far and how many times a year something similar has happened helps find the cause. The National Health Information Portal also treats the time of onset, duration and history of recurrence as important clues in diagnosing stomatitis.

When the ulcer does not heal after 2 to 3 weeks
When the ulcer is larger than 1 cm or several ulcers merge
When stomatitis keeps recurring
When you have a high fever or have trouble swallowing food and water
When ulcers or inflammation are also present in the eyes, skin or genitals
When there is a white or red patch that cannot be wiped away

Detailed guides

Frequently asked questions

How long does stomatitis usually last?

According to the National Health Information Portal, the most common aphthous stomatitis heals within 10 to 14 days without scarring, and Seoul National University Hospital's medical information explains that it heals naturally within 1 to 2 weeks. Herpetic stomatitis usually heals within 2 weeks too. If it goes well beyond this time or keeps getting bigger, get an exam. If it recurs in the same place or the look differs from your usual mouth sore, it is good to have it checked regardless of the duration.

Can a mouth sore spread to other people?

The National Health Information Portal classifies aphthous stomatitis as non-infectious stomatitis, so it is not regarded as a disease that spreads to others. On the other hand, Seoul National University Hospital's medical information explains that herpetic stomatitis is contagious, and the National Health Information Portal describes hand-foot-and-mouth disease as an infectious disease. While blisters are present, it is good to use separate cups and spoons.

Which department should I go to for stomatitis?

Diseases of the oral mucosa are often treated at the dentist, especially oral medicine, and at ENT clinics. Seoul National University Hospital's medical information also lists family medicine, gastroenterology and dermatology as departments related to stomatitis, so if skin or bowel symptoms come with it, consider the matching department as well.

Will taking vitamins cure stomatitis?

The National Health Information Portal explains that if a vitamin B12 or iron deficiency is the cause, supplements can help. The same effect cannot be expected in people without a deficiency, so if stomatitis recurs it is good to first check for a deficiency with a blood test. If supplementation is needed, it is safest to decide which ingredient and how much after an exam.

My child has a sore mouth and blisters on the hands and feet. What should I do?

It may be hand-foot-and-mouth disease. According to the National Health Information Portal, it mainly affects children, the incubation period is 3 to 6 days, and it usually heals by itself in about a week. If mouth pain keeps the child from drinking well, dehydration can develop, so see a pediatrician. If the child has a fever and becomes listless or passes less urine, seek care quickly.

Should I stop brushing when I have stomatitis?

Both the National Health Information Portal and Seoul National University Hospital's medical information advise oral hygiene and cleanliness as the basis of stomatitis care. If the ulcer area hurts, brush that area gently with a soft toothbrush and discuss a less irritating toothpaste or brushing method with the dentist. If the mouth stings after brushing, reduce the amount of toothpaste and rinse well with water.

References

Korean version →