Are mouth ulcers and boils just due to "heatiness"? Understand the causes and prevention methods.

Many people believe that mouth ulcers (commonly known as "canker sores") are merely minor issues caused by "heatiness," but if the ulcers persist without healing or recur frequently, there may be more complex health issues behind them, far beyond just "heatiness." In particular, ulcer symptoms on the tongue are often overlooked, yet this is a common manifestation of mouth ulcers. This article will comprehensively analyse the common symptoms, causes, treatment methods, and daily preventive measures for mouth ulcers, helping everyone to address this bothersome health issue correctly.

Oral ulcers, also known as "recurrent aphthous stomatitis," are commonly referred to as "canker sores." They are small areas of inflammation caused by damage to the oral mucosa. These ulcers often appear on the lips, tongue, gums, and the inside of the cheeks, presenting as round or oval shapes with a whitish or yellowish centre and red, swollen edges. They typically cause pain.

Tongue ulcers are a type of oral ulcer, frequently occurring at the tip, sides, or base of the tongue. They can be particularly painful during eating, speaking, or brushing teeth. In most cases, symptoms resolve naturally within 7 to 14 days. However, if they recur frequently, fail to heal over time, or are accompanied by systemic symptoms such as fever or fatigue, it is advisable to seek medical attention promptly.

It is worth noting that oral ulcers do not appear on the outer lips and are not contagious, distinguishing them from "cold sores." If canker sores appear frequently or persist for more than two weeks without improvement, they may indicate other health issues, and attention should be given to address them.

Typical symptoms of mouth ulcers include:

• The ulcer surface appears white or yellow, with a depressed centre and red, swollen edges.
• Pain intensifies during eating or speaking.
• Ulcers may appear singly or in multiple instances simultaneously, and in severe cases, they may cluster together.
• Some patients may experience accompanying symptoms such as fever, fatigue, or swollen lymph nodes under the jaw.
• Before the ulcer appears, the affected area often feels stinging or burning.

If the mouth ulcer is unusually large, does not heal for a prolonged period, recurs frequently, or is accompanied by systemic symptoms such as fever, it is advisable to seek medical attention as soon as possible.

The causes of mouth ulcers are varied and not necessarily due to "heatiness"; they may reflect underlying health issues:

Traumatic Ulcers

Caused by physical irritation, such as accidental biting, brushing too hard, rubbing from braces or dentures, or burns from hot food. This is the most common type, and the wounds usually heal on their own.

Infectious Ulcers

Caused by bacterial, viral, or fungal infections, often occurring when immunity is low. For example, oral thrush caused by Candida albicans, or multiple ulcers resulting from viral infections.

Immune System Disorders

Conditions such as Behçet's disease, systemic lupus erythematosus, or inflammatory bowel disease—autoimmune disorders—can cause the immune system to attack the body's own tissues, leading to recurrent mouth ulcers often accompanied by systemic symptoms.

Malignant Tumours and Blood Disorders

In rare cases, a persistent single mouth ulcer that does not heal may be an early sign of oral cancer; it could also be related to blood disorders such as anaemia or leukaemia, requiring particular vigilance.

Most oral ulcers can be alleviated with medication to reduce discomfort and speed up healing. Common treatment methods include:

Steroid Anti-inflammatory Drugs

For example, creams or oral patches containing Hydrocortisone or Dexamethasone can help reduce local inflammation and pain, suitable for moderate to severe symptoms.

Non-Steroidal Drugs

For instance, oral sprays or mouthwashes with antibacterial, analgesic, and astringent properties often contain ingredients such as Chlorhexidine or Benzocaine.

Tissue Coagulants

These can form a protective layer on the ulcer surface to reduce friction and relieve pain, ideal for use before eating to enhance comfort.

If the ulcer is accompanied by systemic symptoms such as fever or fatigue, a doctor may recommend oral medication or further tests to identify the underlying cause.

Although most oral ulcers are not serious conditions, they can be extremely painful when they occur, affecting eating and quality of life. To reduce the frequency of outbreaks, consider the following approaches:

• Balanced Diet: Ensure adequate intake of Vitamin B12, iron, folic acid, and zinc to maintain oral mucosal health.
• Avoid Irritating Foods: Minimise consumption of spicy, hard, or acidic foods to prevent aggravating sores.
• Maintain Oral Hygiene: Brush teeth twice daily and use dental floss, opting for a soft-bristled toothbrush to reduce irritation to the mouth.
• Stress Relief: Maintain a regular routine and engage in moderate exercise to help stabilise emotions and the immune system.
• Regular Dental Check-ups: Address sharp tooth edges or ill-fitting braces promptly to prevent oral injuries caused by friction.

Recurrent mouth ulcers may be associated with chronic diseases or other underlying health issues. If a CT or MRI scan is required, the cost at private hospitals starts from HKD 6,000, and can go as high as HKD 40,000 if contrast agents are used or if the scope of the examination is broader. While public hospitals charge lower fees, the waiting times are long and services are subject to certain restrictions.

Voluntary Health Insurance Scheme (VHIS) covers "prescribed diagnostic imaging tests," allowing you to claim reimbursement even without hospitalisation, and offers tax deduction benefits. This provides more flexible and high-quality medical arrangements when treatment is needed. If you wish to learn about the most suitable medical protection plan for yourself, feel free to consult 10Life licensed insurance advisors for impartial and professional advice.

Further Reading:
What to Do About Frequent Headaches? Understanding Symptoms, Types, Causes, and Relief Methods
Does My Child Have Autism? Understanding Early Signs and Assessment Processes
【Affordable Medical Insurance】How to Choose Medical Insurance and Maximise Claims with Ward Plans

References:
1.Mayo Clinic. Mouth Ulcers
2.OT&P Healthcare. Mouth Ulcers
3.Hong Kong 01. Public Hospital Price Increases | Don’t Want to Wait for Tests? A Guide to CT/MRI Fees at Public and Private Hospitals

Last Updated: 3 November 2025

This English version of this article has been generated by machine translation powered by AI. It is provided solely for reference purposes. In the event of any discrepancy or inconsistency between this translation and the original Chinese version, the Chinese version shall prevail.