By Dr. Drub T. Sharma, MDS (Oral & Maxillofacial Surgery), Fellow in Oral Oncology & Reconstructive Surgery
Most people develop a mouth ulcer at some point in their lives. These painful sores can appear on the tongue, cheeks, lips, gums, or the floor of the mouth. In many cases, they are harmless and heal naturally within 7 to 14 days.
However, a mouth ulcer that persists for more than two weeks should never be ignored.
While persistent ulcers may still be caused by trauma, infection, or nutritional deficiencies, they can also be an early warning sign of oral cancer, a condition where early diagnosis dramatically improves treatment outcomes.
India has one of the highest burdens of oral cancer worldwide, largely because of tobacco use, areca nut (supari), and alcohol consumption. The encouraging news is that many oral cancers can be detected at an early stage through a careful clinical examination and, when necessary, a biopsy.
This guide explains the difference between a harmless ulcer and one that needs urgent evaluation, helping you recognise when it is time to consult an oral and maxillofacial surgeon.
What Is a Mouth Ulcer?
A mouth ulcer is a break in the lining of the mouth that exposes the underlying tissue. Unlike simple redness or irritation, an ulcer represents a true loss of the protective mucosal layer.
They commonly occur on:
- Inside of the cheeks
- Tongue
- Lips
- Floor of the mouth
- Soft palate
- Gums
Most ulcers are painful, especially while eating spicy or acidic foods, and heal without leaving any permanent damage.
How Long Should a Mouth Ulcer Last?
This is one of the most important questions patients ask.
| Type of Ulcer | Typical Healing Time |
|---|---|
| Minor aphthous ulcer | 7–10 days |
| Traumatic ulcer | 7–14 days (after removing the cause) |
| Viral ulcer | 7–14 days |
| Large aphthous ulcer | Up to 3 weeks |
| Ulcer lasting more than 2 weeks | Needs professional evaluation |
Although not every persistent ulcer is cancerous, any ulcer that has not healed within two weeks should be examined by a qualified dental professional or oral and maxillofacial surgeon. Early assessment helps identify the cause and, if needed, allows timely treatment.
Common Causes of Mouth Ulcers
Understanding the possible causes helps explain why most ulcers are not cancer.
1. Accidental Trauma
This is the most common reason for a mouth ulcer.
Examples include:
- Accidentally biting your cheek
- Sharp or broken teeth
- Poorly fitting dentures
- Broken fillings
- Orthodontic braces
- Aggressive tooth brushing
Once the source of trauma is corrected, these ulcers usually heal within two weeks.
2. Recurrent Aphthous Ulcers (Canker Sores)
These are the classic “mouth ulcers” that many people experience.
Typical features include:
- Small round ulcers
- White or yellow centre
- Red border
- Very painful
- Usually occur on non-keratinised tissues such as the inside of the lips or cheeks
The exact cause is not fully understood, but contributing factors include stress, genetics, and immune system responses.
3. Nutritional Deficiencies
Deficiencies of certain nutrients can increase the likelihood of recurrent ulcers, including:
- Iron
- Vitamin B12
- Folate
People with frequent mouth ulcers may benefit from evaluation for underlying nutritional deficiencies if clinically indicated.
4. Viral Infections
Some viral infections can cause multiple painful ulcers.
Examples include:
- Herpes simplex virus
- Hand, Foot and Mouth Disease
- Varicella-zoster virus
These are often accompanied by fever, malaise, or skin lesions.
5. Autoimmune Conditions
Persistent or recurrent ulcers may be associated with conditions such as:
- Behçet disease
- Oral lichen planus
- Pemphigus vulgaris
- Mucous membrane pemphigoid
These conditions require specialist diagnosis and long-term management.
6. Tobacco and Areca Nut (Supari)
Smoking, smokeless tobacco, gutkha, khaini, paan with tobacco, and areca nut products significantly increase the risk of changes in the oral lining.
Long-term exposure can lead to potentially malignant disorders such as leukoplakia and oral submucous fibrosis, which require prompt evaluation and regular follow-up.
When Should You Be Concerned?
Not every mouth ulcer is cancer.
However, certain features deserve immediate attention.
The following warning signs do not confirm cancer, but they indicate that you should seek professional evaluation without delay.
Warning Sign #1: The Ulcer Has Not Healed After Two Weeks
This is the single most important warning sign.
A normal ulcer should show clear improvement within two weeks. If it persists despite avoiding trauma or using standard ulcer treatments, it should be examined by an experienced clinician.
Waiting for “just another week” can delay diagnosis if a more serious condition is present.
Rule to remember:
Any mouth ulcer that persists for more than two weeks deserves professional evaluation.
Warning Sign #2: The Ulcer Has Raised or Rolled Edges
Most ordinary ulcers have flat, smooth borders.
An ulcer with:
- Raised edges
- Thickened margins
- Rolled borders
- A firm surrounding rim
may indicate abnormal tissue changes and should be assessed promptly.
During examination, your surgeon will also gently feel the area to determine whether there is underlying firmness (induration), an important clinical finding.
Warning Sign #3: The Ulcer Is Painless
This surprises many people.
Most harmless mouth ulcers are painful.
In contrast, early oral cancers may cause little or no pain, which is one reason they can go unnoticed.
If you have a painless sore that does not heal, particularly if you smoke, chew tobacco, or consume areca nut, do not ignore it simply because it is not hurting.
Warning Sign #4: There Is a White or Red Patch Around the Ulcer
Persistent:
- White patches (leukoplakia)
- Red patches (erythroplakia)
- Mixed red-and-white patches
may represent potentially malignant disorders or, in some cases, early cancerous changes.
These lesions should always be evaluated by an oral medicine specialist or oral and maxillofacial surgeon.
Warning Sign #5: The Ulcer Bleeds Easily
Minor ulcers can bleed if accidentally bitten or brushed.
However, an ulcer that:
- Bleeds spontaneously
- Bleeds with minimal contact
- Continues bleeding repeatedly
requires prompt clinical assessment.
Fragile tissue can occur in inflammatory conditions, infections, and cancers, making examination essential to determine the underlying cause.
Ask Dr. Drub Sharma
Doctor, What’s the Biggest Mistake Patients Make with Mouth Ulcers?
“The biggest mistake is assuming every mouth ulcer is harmless. Most ulcers heal within two weeks. If one doesn’t, especially if you use tobacco or alcohol, don’t keep waiting or self-medicating. Early evaluation can make all the difference.”
When Should Someone Worry About a Mouth Ulcer?
“Any ulcer that lasts longer than two weeks, keeps coming back in the same spot, bleeds easily, or is associated with a white or red patch should be examined by an oral cancer specialist. It may not be cancer, but it should never be ignored.”
If You Could Give Every Patient One Piece of Advice, What Would It Be?
“Don’t wait for pain before seeking help. Early oral cancer is often painless. A simple examination today could prevent extensive treatment tomorrow. Early detection saves lives.”
| Feature | Normal Mouth Ulcer | Possible Oral Cancer |
|---|---|---|
| Duration | 7–14 days | More than 2 weeks |
| Pain | Usually painful | May be painless |
| Healing | Improves gradually | Doesn’t heal |
| Borders | Smooth | Raised or rolled |
| Bleeding | Rare | Bleeds easily |
| Lump | No | May be present |
| Neck swelling | No | May occur |
| Needs biopsy | Rarely | Often recommended |
Concerned About a Mouth Ulcer That Won’t Heal?
A mouth ulcer that persists for more than two weeks should never be ignored. While many ulcers are harmless, some may be early signs of a potentially serious condition, including oral cancer.
At Maxora Superspeciality Clinic, Sion, Mumbai, Dr. Drub T. Sharma, Oral & Maxillofacial Surgeon and Oral Oncology Specialist, offers comprehensive oral cancer screening, expert diagnosis, biopsy (when indicated), and personalized treatment planning using advanced diagnostic technology and evidence-based care.
Schedule Your Oral Cancer Screening Today
Because early detection doesn’t just improve treatment—
it can save your smile, your quality of life, and even your life.
If you have a persistent mouth ulcer, a white or red patch, unexplained swelling, or any unusual change inside your mouth, don’t wait for it to become painful. Get it evaluated by a specialist.
