Aphthous Ulcers: Symptoms, Causes & Treatment

Aphthous ulcers, also known as mouth ulcers or canker sores, are small, painful sores that appear on the soft tissues inside the mouth, such as the inner cheeks and lips, under the tongue, and the base of the gums. They are among the most common mouth problems, and many people experience them repeatedly. It is very important to know that aphthous ulcers are not contagious (unlike herpes sores that appear on the outer lip), are not dangerous, and have no connection to cancer in most cases.

An aphthous ulcer usually appears as a small round or oval sore, white or yellowish in the center, surrounded by a red edge or halo, and is painful especially when eating, drinking, talking, or when hot or sour food touches it. One ulcer or several ulcers may appear at the same time. Although its exact cause is not fully understood, there are known factors that trigger its appearance or increase its recurrence, including: stress and psychological tension, minor mouth injuries (such as biting the cheek or brushing teeth forcefully), deficiency of some vitamins and minerals (such as iron, vitamin B12, and folic acid), some sour or spicy foods, hormonal changes, and sometimes sensitivity to an ingredient in toothpaste.

In most cases, aphthous ulcers heal on their own within days to two weeks without leaving a scar, and need no treatment other than relieving pain and discomfort. Relief measures include: avoiding spicy, sour, and crunchy foods, gargling with warm salt water, using a topical soothing or protective ointment or gel for the ulcer, sometimes mouthwashes, and gently caring for mouth hygiene. For severely recurrent cases, the doctor may look for an underlying cause such as a vitamin deficiency and treat it. It is important to see a doctor or dentist if the ulcer is very large or unusually painful, has not healed within two to three weeks, recurs very severely, or is accompanied by fever or general symptoms, as these cases may need evaluation to confirm their nature.

• A small round white or yellow sore surrounded by a red halo.
• Pain especially when eating, drinking, and talking.
• One ulcer or several may appear together.
• Not contagious and heal without a scar.

• Stress and psychological tension.
• Minor mouth injuries (biting the cheek, brushing teeth forcefully).
• Deficiency of some vitamins and minerals (iron, B12, folic acid).
• Sour or spicy foods, hormonal changes, and sometimes sensitivity to a toothpaste ingredient.

• Diagnosis is often clinical from the ulcer's appearance and location.
• Testing for vitamin deficiency with severe recurrence.
• Evaluating any ulcer that does not heal within 2–3 weeks to exclude other causes.

Symptom relief (they heal on their own)

• Avoiding spicy, sour, and crunchy foods.
• Gargling with warm salt water.
• Topical soothing or protective ointments or gel, and sometimes mouthwashes.

Severely recurrent cases

• Looking for an underlying cause (such as a vitamin deficiency) and treating it.

This content is educational and does not replace consulting a doctor or dentist.

• Pain affecting eating and talking temporarily.
• A secondary infection rarely.
• Bothersome recurrence affecting quality of life.

• Managing stress and avoiding known dietary triggers.
• Gently brushing teeth and avoiding mouth injuries.
• Correcting vitamin and mineral deficiencies when present.