Approach to mouth ulcers
- Approach to a complaint
Most mouth ulcers are aphthous or viral and heal in 1 to 3 weeks; an ulcer that does not heal must be biopsied to rule out cancer.
See it in 3D: Tongue
What it is
Mouth ulcers are breaks in the oral mucosa. Nearly all are aphthous ulcers, trauma or viral infections and heal on their own. The doctor must recognise three situations: the ulcer that does not heal and may be a squamous cell carcinoma, above all in smokers and drinkers; recurrent ulcers that signal a systemic disease (nutritional deficiencies, coeliac or inflammatory bowel disease, Behçet); and ulcers in immunosuppressed or neutropenic patients. The NIDCR advises seeing a dentist or doctor if a mouth lesion lasts more than 2 weeks.
Key questions in the history
- How long has the ulcer been there? First time or recurrent?
- Single or several? Painful?
- Any trauma: ill-fitting denture, broken tooth, bite?
- Does the patient smoke, chew tobacco or drink alcohol?
- Genital ulcers, skin lesions, red eye, diarrhoea or fever?
- New drugs, or immunosuppression (HIV, chemotherapy)?
Causes and classification
- Recurrent aphthous ulcers (aphthous stomatitis).
- Traumatic: ill-fitting denture, broken teeth, bites.
- Infectious: herpes simplex, hand, foot and mouth disease and herpangina, candidiasis, syphilis, tuberculosis and HIV.
- Systemic: Behçet, coeliac disease, inflammatory bowel disease, iron, folate or B12 deficiency and neutropenia.
- Mucocutaneous: lichen planus, pemphigus vulgaris and mucous membrane pemphigoid.
- Neoplastic: oral squamous cell carcinoma and premalignant lesions (leukoplakia, erythroplakia).
- Drug-related: chemotherapy, among others.
Step-by-step approach
- Ask about duration, number, recurrence and triggers; look for local trauma.
- Examine the whole mouth with good light and gloves: tongue (edges and floor of mouth), gums, palate and oropharynx.
- Palpate the ulcer for induration and palpate the neck nodes.
- Look for skin, genital and eye lesions, and ask about gut symptoms.
- If there is trauma, remove the cause and review in 2 weeks.
- If the ulcer has not healed in 2 weeks, is indurated or there is a white or red patch: refer for biopsy.
- Recurrent or multiple ulcers: full blood count, iron, folate, vitamin B12 and a targeted search for systemic disease.
- Child with vesicles and ulcers and fever: herpes or enterovirus; supportive care and fluids.
Causes of mouth ulcers
| Cause | Clues | Management |
|---|---|---|
| Aphthous ulcer (recurrent aphthous stomatitis) | Small, painful, white centre and red border, recurrent | Chlorhexidine mouthwash or topical corticosteroid; workup if very frequent |
| Herpes simplex | Grouped vesicles, fever; gingivostomatitis in children | Supportive care and fluids; antiviral if early or severe |
| Hand, foot and mouth disease | Child with mouth ulcers and lesions on hands and feet | Supportive care and fluids |
| Candidiasis | White plaques that rub off; dentures, inhaled corticosteroid or immunosuppression | Topical antifungal (nystatin) or fluconazole |
| Behçet disease | Recurrent aphthous ulcers with genital ulcers and uveitis | Referral to rheumatology |
| Oral squamous cell carcinoma | Indurated ulcer that does not heal, smoker or drinker | Biopsy; priority referral |
Red flags
- Ulcer that has not healed in 2 weeks.
- Indurated or raised edge, or fixed to deep tissues.
- White or red patch that does not rub off.
- Associated neck node, earache or dysphagia.
- Smoker or drinker over 40 years.
- Child refusing fluids: risk of dehydration.
- Fever with extensive ulcers in an immunosuppressed or neutropenic person.
Next step / Initial management
- Single ulcer with a traumatic cause: remove the cause and review in 2 weeks; if it persists, biopsy.
- Aphthous ulcers: gentle rinses, avoid hot or spicy food; chlorhexidine or topical corticosteroids for severe cases.
- Recurrent ulcers: full blood count, ferritin, folate and vitamin B12; tests for coeliac or inflammatory bowel disease if symptoms suggest them.
- Refer as a priority (within days) to ENT, oral surgery or head and neck any ulcer not healed in 2 weeks, indurated, or with a red or white patch.
- Urgent referral for dehydration in a child, or fever with ulcers in a neutropenic patient.
Test yourself
Think of the answer, then tap the question to see it.
A 60-year-old man who smokes and drinks has had an indurated ulcer on the side of his tongue for 5 weeks. Next step?
Priority referral for biopsy: an indurated ulcer that has not healed in 2 weeks in a smoker and drinker suggests squamous cell carcinoma.
How long does a typical aphthous ulcer take to heal?
Pain fades in 7 to 10 days and full healing takes 1 to 3 weeks; large ulcers take longer.
A woman has recurrent mouth ulcers, genital ulcers and uveitis. Which diagnosis must be ruled out?
Behçet disease; refer to rheumatology.
Which nutritional deficiencies are linked to recurrent aphthous ulcers?
Iron, folic acid and vitamin B12.
Connections
See it in 3D1
The structures of Durgical's 3D anatomy where it is found.
Educational content; it does not replace a medical assessment and is not a clinical instruction. For a real case, follow current guidelines and specialist advice.
Sources: Oral Cancer (National Institute of Dental and Craniofacial Research (NIDCR), NIH, 2024); Canker sore (MedlinePlus Medical Encyclopedia) (U.S. National Library of Medicine, NIH, 2025).
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Representative model, for educational purposes only.