Oral ulcers are open sores that form on the soft mucosal lining of the mouth, including the inner cheeks, tongue, gingiva, palate, and lips. They range from minor, self-limiting lesions to persistent wounds that may signal an underlying systemic condition.
Types and Common Causes
The most frequently encountered form is recurrent aphthous stomatitis — commonly called canker sores — which presents as shallow, round ulcerations with a white or yellow center surrounded by an erythematous halo. Beyond aphthous lesions, oral ulcers arise from a broad range of triggers:
- Trauma — accidental cheek biting, sharp tooth edges, ill-fitting dentures, or orthodontic appliances abrading soft tissue
- Viral infection — herpes simplex virus produces clusters of small ulcers, typically on keratinized mucosa near the lips and hard palate
- Systemic disease — Crohn’s disease, celiac disease, lupus, and Behçet syndrome are associated with persistent or recurrent oral ulceration
- Nutritional deficiencies — low levels of vitamin B12, folate, iron, or zinc impair mucosal integrity and delay healing
- Drug reactions — certain medications, including NSAIDs and beta-blockers, have been linked to ulcerative mucosal changes
Clinical Significance
Most minor oral ulcers resolve within 7 to 14 days without intervention. However, any ulcer persisting beyond three weeks requires thorough evaluation to rule out malignancy, since oral squamous cell carcinoma can present as a non-healing ulceration. Clinicians typically assess lesion borders, induration, and associated lymphadenopathy, with biopsy indicated when the picture is unclear.
Xerostomia — dry mouth — can delay mucosal healing and intensify ulcer discomfort, while compromised periodontal health may complicate diagnosis when ulcers involve the gingival tissues. Pain from oral ulcers frequently disrupts adequate plaque removal, creating a secondary risk of infection around the lesion site.
Management
Mild cases often respond to topical anesthetics, antimicrobial mouthrinses, or corticosteroid gels that reduce inflammation and accelerate tissue closure. For recurrent or severe presentations, systemic agents or referral to an oral medicine specialist may be warranted. Identifying and eliminating contributing factors — whether a sharp restoration, a systemic trigger, or a nutritional gap — remains the cornerstone of long-term care.
Persistent or atypical oral ulcers should never be dismissed; early evaluation by a clinician is the most reliable way to distinguish a benign lesion from one requiring urgent intervention.