Clinical case
A 22-year-old woman presents to the dental clinic complaining of recurrent painful mouth ulcers since her teenage years. The ulcers occur every few months and typically affect the inside of her lips and cheeks. She reports difficulty eating spicy foods during episodes but is otherwise well. On examination there are two small round ulcers on the lower labial mucosa with yellow-grey fibrinous bases surrounded by erythematous haloes. No skin lesions, genital ulcers or systemic abnormalities are identified.
Pathophysiology
The precise cause of recurrent aphthous stomatitis (RAS) remains unclear. It is thought to result from a dysregulated cell-mediated immune response (similar to type III and IV reactions) occurring in susceptible individuals.
Key mechanisms include:
T-lymphocyte-mediated destruction of oral epithelial cells.
Increased production of pro-inflammatory cytokines, particularly tumour necrosis factor-alpha (TNF-α).
Genetic predisposition, with a positive family history reported in many patients.
Mucosal immune dysfunction leading to an exaggerated inflammatory response to triggering factors.
Local trauma acting as a precipitating factor in susceptible individuals.
Nutritional deficiencies contributing to impaired mucosal integrity and repair.
Association with systemic conditions such as coeliac disease, inflammatory bowel disease and HIV infection.
The condition is not infectious and is characterised by recurrent episodes of ulceration separated by periods of complete healing.
Epidemiology and Risk Factors
Recurrent aphthous stomatitis affects approximately 10-25% of the population making it one of the most common oral mucosal diseases. Possible aetiological factors include:
Genetic predisposition
Exaggerated response to trauma
Infections
HIV, EBV
Immunological abnormalities
Gastrointestinal disorders
Coeliac disease, Inflammatory bowel disease
Haematological deficiencies
Haematinic deficiencies(most commonly due to Iron, Vitamin B12 and folate deficiencies)
Hormonal disturbances
Stress
Clinical Features
Minor aphthae ulcers
Most common form (approximately 80% of cases).
Less than 10 mm in diameter.
Occur on non-keratinised mucosa.
Round or oval ulcers with a yellow-grey fibrinous base and erythematous halo.
Heal within 7-14 days without scarring.
Usually present as one to five ulcers at a time.
Major aphthae ulcers
Larger than 10 mm in diameter.
Deeper and more painful than minor aphthae.
May persist for several weeks to months.
Can occur anywhere within the oral cavity, including keratinised mucosa.
Often heal with residual scarring.
May significantly impair eating, drinking and speech.
Herpetiform aphthae ulcers
Least common form.
Characterised by multiple small ulcers (typically 1-3 mm).
May occur in crops of 10-100 lesions.
Frequently coalesce to form larger irregular ulcerated areas.
Despite the name, they are unrelated to herpes simplex virus infection.
Heal without scarring in most cases.
Investigations
Investigations are generally unnecessary in mild uncomplicated disease. There is no gold standard investigation and aphthous stomatitis is primarily a clinical diagnosis based on the history and characteristic appearance of the recurrent oral ulceration, after excluding alternative causes of recurrent oral ulcerations.
Normally increasing frequency of ulcers brings the patient to seek treatment. Majority of patients appear well however further investigations can be done to investigate potential risk factors/if the diagnosis is uncertain, including:
Routine bloods - Full blood count (FBC - to rule out anaemia), Vitamin B12, Ferritin, Folate, CRP/ESR (where systemic disease is suspected)
Coeliac serology - IgA tissue transglutaminase (IgA-tTG)
Viral serology e.g. EBV or HIV testing (severe, persistent or atypical ulceration)
Biopsy of persistent, atypical or non-healing ulcers