Aphthous Ulcers: Clinical Appearance and Identification
Aphthous ulcers typically appear as well-demarcated, oval or round ulcers with a white or yellow pseudomembrane surrounded by an erythematous halo. 1
Types of Aphthous Ulcers
Aphthous ulcers can be classified into three main clinical forms:
Minor aphthous ulcers:
- Most common type
- Less than 10 mm in diameter
- Heal within 7-10 days without scarring 2
- Usually appear as round/oval lesions with white/yellow center
- Surrounded by erythematous halo
Major aphthous ulcers:
- Larger than 10 mm in diameter
- Can persist for several weeks to months
- May cause scarring 2
- More painful and debilitating
Herpetiform aphthous ulcers:
- Multiple small clustered ulcers
- Can coalesce to form larger irregular ulcers
Distinguishing Features
Aphthous ulcers have specific characteristics that help distinguish them from other oral lesions:
- White or yellow depressed center
- Surrounded by a halo of erythema 1
- Well-demarcated borders
- Typically painful
- Can be isolated or multiple 1
Location
Aphthous ulcers commonly appear on:
- Buccal mucosa (cheeks)
- Labial mucosa (lips)
- Tongue
- Floor of mouth
- Soft palate
- Less commonly on keratinized gingiva or hard palate
Differential Diagnosis
It's important to distinguish aphthous ulcers from other oral ulcerative conditions:
- Traumatic ulcers: Associated with identifiable cause, shape corresponds to traumatic agent
- Herpetic lesions: Usually preceded by vesicles, clustered appearance
- Oral tuberculosis: Stellate shape with undermined edges 1
- Oral cancer: Indurated borders, non-healing, often unilateral
- Crohn's disease: May present with oral ulcers that coincide with abdominal symptoms 1
- Behçet's disease: Recurrent bipolar aphthosis (oral and genital) 3
When to Consider Further Evaluation
Biopsy or further testing should be considered for oral ulcers that:
- Persist beyond 2 weeks 4
- Are unusually large or painful
- Are accompanied by systemic symptoms
- Do not respond to conventional treatment
- Recur frequently (4+ times per year) 3
Laboratory Testing for Persistent Ulcers
For persistent or recurrent ulcers, consider:
- Full blood count (to identify blood disorders)
- Fasting blood glucose (diabetes can predispose to fungal infections)
- HIV antibody testing
- Syphilis serology 4
Common Pitfalls in Diagnosis
- Assuming all oral ulcers are benign without proper evaluation
- Delaying evaluation of persistent ulcers
- Failing to consider systemic diseases that can present with oral ulcers 4
- Not recognizing that recurrent aphthous stomatitis may be associated with gastrointestinal diseases, nutritional deficiencies, or immune disorders 3
Proper identification of aphthous ulcers is essential for appropriate management and to rule out more serious conditions that may present with similar oral manifestations.