Aphthous Stomatitis: Causes, Symptoms, and Treatment
Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Aphthous Stomatitis?
A dentist or a doctor who treats mouth problems can diagnose canker sores. Mild sores are often handled with home care. Severe or repeated outbreaks may need a dentist or a skin doctor. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is aphthous stomatitis?
Aphthous stomatitis is the medical name for canker sores. A canker sore is also called an aphthous ulcer. A canker sore is a painful, open sore in the mouth. Canker sores are white or yellow and surrounded by a bright red area. They are not cancerous. They are also not contagious, which means they do not spread from person to person.
They most often appear on the inner surface of the cheeks and lips, the tongue, the upper surface of the mouth, and the base of the gums. Most are small, often under one third inch (1 centimeter) across. Anyone can get them. Women are more likely to get them than men, and they may run in families.
Symptoms
Signs include:
- One or more painful, red spots or bumps that develop into an open ulcer.
- A white or yellow center that turns gray as healing starts.
- Pain from the open sore, which can hurt while it heals.
The pain often goes away in 7 to 10 days. A sore can take 1 to 3 weeks to fully heal. Less common symptoms include fever, swollen lymph nodes, and a general feeling of being unwell.
Causes and who gets it
The exact cause is uncertain. They may occur with viral infections, or be linked to problems with the body's immune system. Some experts believe immune system problems, bacteria, or viruses may be involved. Common triggers include:
- Mouth injury from dental work.
- Cleaning the teeth too roughly.
- Biting the tongue or cheek.
- Emotional stress.
- Low levels of iron, folic acid, or vitamin B-12 in the diet.
- Hormonal changes.
- Food allergies.
How doctors diagnose it
A doctor can often make the diagnosis by looking at the sore. If sores persist or keep coming back, tests can look for other causes, such as erythema multiforme, medicine allergies, herpes infection, and bullous lichen planus. A canker sore is not the same as a cold sore (fever blister).
Treatment
In most cases, canker sores go away without treatment. Avoid hot or spicy foods, which can cause pain. Acidic foods can also irritate a sore. Over-the-counter medicines can ease the pain, such as numbing mouth rinses or drops. Salt water or mild, alcohol-free mouthwashes may help. A doctor may prescribe stronger medicine for severe cases, including chlorhexidine mouthwash and corticosteroids placed on the sore or taken as a pill. Brush twice a day, floss daily, and get routine dental check-ups.
When to see a doctor
Contact a doctor or dentist if a sore does not go away after 2 weeks of home care or gets worse. Also call if you get canker sores more than 2 or 3 times a year, or if you have fever, diarrhea, headache, or a skin rash with the sore. Get care right away for a mouth ulcer that does not heal, because some cancers can first appear as a mouth ulcer that does not heal.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. A primary care doctor can check whether repeated sores point to a low vitamin level or another health problem. They can also arrange follow-up and refer you to a dentist or specialist when sores keep coming back.
Common questions
Are canker sores contagious?
No, they are not contagious. They do not spread from person to person. This is one key difference from cold sores (fever blisters).
How long does a canker sore last?
The pain often goes away in 7 to 10 days. A sore can take 1 to 3 weeks to fully heal. Large ulcers can take longer. See a doctor if a sore does not go away after 2 weeks of home care.
Are canker sores a sign of cancer?
No, canker sores are not cancer and do not cause cancer. But some types of cancer may first appear as a mouth ulcer that does not heal. Any ulcer that does not heal needs an exam.
What foods should I avoid with a canker sore?
Try not to eat hot or spicy foods, which can cause pain. Acidic foods can also irritate the sore. Avoid mouthwashes that contain alcohol, which can irritate the area more.
Sources
- MedlinePlus Medical Encyclopedia - Canker sore
- American Dental Association MouthHealthy - Canker Sores
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
