Aphthous Ulcers

Aphthous ulcers are a common, recurrent condition characterised by painful, shallow ulceration of the non-keratinised oral mucosa. The underlying aetiology is uncertain but likely multifactorial.

They occur either as an idiopathic, isolated recurrent condition (recurrent aphthous stomatitis, by far the commonest presentation in clinical practice) or, in a smaller proportion of cases, as a manifestation of an underlying systemic condition.

The great majority of cases are reassuring and self-limiting. Careful clinical assessment for specific red flag features and relevant associated systemic symptoms is essential to identify the minority of presentations warranting further, targeted investigation.

Classification and pathophysiology

• Minor aphthous ulcers, the commonest subtype, are small (generally under 1 cm), shallow ulcers with a grey-white fibrinous base and surrounding erythematous halo. They typically heal within one to two weeks without scarring.
• Major aphthous ulcers are larger, deeper, more painful, and slower healing (often taking several weeks), with a higher likelihood of scarring.
• Herpetiform aphthous ulcers are numerous, small, clustered ulcers that may coalesce. They superficially resemble herpetic ulceration, despite the entirely unrelated, non-infective aetiology reflected in the subtype's name.
• The precise pathophysiology of idiopathic recurrent aphthous stomatitis remains incompletely understood. It is believed to reflect a localised, T-cell mediated immune response against the oral mucosal epithelium.
• Triggers or exacerbating factors include local trauma, specific nutritional deficiencies (iron, vitamin B12, and folate), stress, hormonal fluctuation, and, in a subset of patients, specific food sensitivities.
• Recurrent oral ulceration can be a manifestation of an underlying systemic condition. These include inflammatory bowel disease (particularly Crohn disease), coeliac disease, Behçet disease (where oral ulceration is a core diagnostic feature), and cyclic neutropenia.
• In severe immunosuppression, consider atypical or unusually severe and persistent presentations related to HIV infection or other significant immunocompromise.

• The characteristic presentation is painful, shallow, round or oval ulcers with a yellow-grey fibrinous base and surrounding erythematous halo, affecting the non-keratinised oral mucosa.
• Sites affected are the buccal mucosa, labial mucosa, ventral tongue, and soft palate. The keratinised mucosa of the hard palate and attached gingiva is characteristically spared, a useful distinguishing feature from several other causes of oral ulceration.
• Pain is frequently disproportionate to the apparent size of the ulcer, with particular discomfort when eating, drinking, and speaking.
• Idiopathic recurrent aphthous stomatitis follows a typical, recurrent pattern. Individual episodes heal over one to several weeks (according to subtype) before recurring at variable intervals.
• The majority of affected individuals have onset during childhood or adolescence. Episode frequency reduces with advancing age in many, though not all, patients.
• Features suggesting an underlying systemic association, warranting further, targeted investigation, include unusually severe, persistent, or treatment-refractory ulceration and ulceration extending onto keratinised mucosa.
• Associated genital ulceration raises suspicion for Behçet disease. Associated gastrointestinal symptoms raise suspicion for inflammatory bowel disease or coeliac disease.
• Significant systemic symptoms (fever, weight loss, or recurrent infection) raise suspicion for cyclic neutropenia or significant immunocompromise.
• Onset of new, significant oral ulceration for the first time in adulthood, without a childhood or adolescent history of recurrent aphthous stomatitis, is also a red flag.

• Diagnosis of typical, idiopathic recurrent aphthous stomatitis is predominantly clinical, based on the characteristic appearance, distribution, and recurrent pattern of ulceration. No specific investigation is routinely needed in a straightforward, typical presentation without red flag features.
• Screening blood tests are a reasonable initial investigation in patients with more frequent, severe, or persistent recurrent aphthous stomatitis. They comprise full blood count and haematinics (iron, vitamin B12, and folate), together with coeliac serology.
• The rationale is the recognised association with these nutritional deficiencies and with coeliac disease, and the potential for symptomatic improvement with correction of an identified deficiency.
• Further, targeted investigation is directed at a specific suspected underlying systemic association, according to the clinical context and any identified red flag features. Examples are gastrointestinal investigation where inflammatory bowel disease is suspected, or specific assessment where Behçet disease or another systemic condition is suggested by the broader clinical picture.
• Biopsy is generally not required for typical, straightforward recurrent aphthous stomatitis.
• Consider biopsy for any persistent, atypical, or non-healing ulcer, particularly in an older patient or with any other feature raising concern for an alternative diagnosis including malignancy. Excluding malignancy is essential in any persistent oral ulceration not following the expected, typical healing pattern.

• Topical corticosteroid preparations (including triamcinolone in an adhesive dental paste base, or a topical corticosteroid mouthwash or spray) are first line treatment for symptomatic relief and to support more rapid healing. Apply directly to the affected ulcer; treatment is most effective when initiated early in an individual episode.
• Topical analgesic and coating agents, including benzydamine mouthwash and other topical local anaesthetic preparations, provide symptomatic pain relief. They are particularly valuable to support adequate oral intake during a painful episode.
• Chlorhexidine mouthwash may reduce secondary bacterial infection and support overall symptomatic improvement.
• Correct any underlying nutritional deficiency (iron, vitamin B12, or folate) identified on screening. A proportion of patients have a meaningful reduction in recurrent ulceration frequency and severity after correction.
• More severe, frequent, or persistent recurrent aphthous stomatitis not adequately responding to topical treatment may warrant specialist oral medicine referral.
• Systemic treatment options (including colchicine, or, for the most severe, refractory cases, systemic immunosuppression) are considered under specialist guidance for selected, significantly affected patients.
• Manage any confirmed underlying systemic association (inflammatory bowel disease, coeliac disease, Behçet disease, or another identified relevant condition) by the standard principles for that condition. Effective treatment of the systemic condition frequently produces meaningful improvement in the oral ulceration.
• Dietary trigger avoidance is a reasonable, low risk adjunct where the patient identifies a specific, consistent food association. Certain foods, including citrus fruits, tomatoes, and specific food additives, are sometimes reported as triggers.
• Minimise local oral trauma, including from ill-fitting dental appliances or a habitual cheek or lip biting pattern.