What is the best approach to diagnose and treat aphthous ulcers in patients, considering their medical history, symptoms, and potential underlying conditions?

Diagnosis and Treatment of Aphthous Ulcers

For typical recurrent aphthous ulcers (RAU), start with topical corticosteroids after antiseptics fail; for ulcers persisting beyond 2 weeks or not responding to 1-2 weeks of treatment, obtain blood tests and consider biopsy to exclude systemic disease or malignancy. 1

Diagnostic Approach

Initial Clinical Assessment

Document these specific ulcer characteristics: 1, 2

• Morphology: Well-demarcated, oval or round ulcers with white/yellow pseudomembrane and surrounding erythematous halo (classic for RAU) 1
• Size and classification: Minor (<1 cm), major (>1 cm), or herpetiform (multiple small ulcers) 3, 4
• Location: RAU typically occur on non-keratinized mucosa (buccal mucosa, tongue, soft palate); fixed keratinized mucosa involvement suggests other diagnoses 3
• Duration: Note if ulcers persist beyond the typical 7-14 day healing period 1
• Pattern: Frequency of recurrence (recurrent aphthous stomatitis defined as ≥4 episodes per year) 4

Identify Traumatic Factors

Check for corresponding mechanical causes where ulcer location and shape match the stimulating factor (sharp tooth edges, dental appliances, thermal/chemical injury) 1, 2

When to Pursue Comprehensive Workup

Obtain blood tests and consider biopsy for: 1, 2

• Ulcers persisting >2 weeks
• Ulcers not responding to 1-2 weeks of appropriate treatment
• Atypical features (stellate shape, undermined edges, indurated borders)
• Recurrent severe presentations
• Associated systemic symptoms

Required Blood Tests

Before any biopsy, obtain: 1, 5

• Full blood count: Detects anemia, leukemia, neutropenia 1, 5
• Coagulation studies and fasting glucose: Exclude biopsy contraindications; hyperglycemia suggests fungal infection risk 1
• HIV antibody and syphilis serology: Rule out infectious causes 1, 5
• Iron, folate, vitamin B12: If anemia suspected 1, 5
• Serum autoantibodies (Dsg1, Dsg3, BP180, BP230): If bullous disease suspected 1, 5

Biopsy Technique

When indicated: 1

• Perform multiple biopsies if ulcers at different sites have varying morphology
• Ensure adequate depth and size (superficial or small biopsies miss diagnostic features) 2, 5
• Include direct immunofluorescence for suspected autoimmune conditions 2, 5

Treatment Algorithm

First-Line: Topical Therapy

For typical RAU, initiate topical treatment in this sequence: 3, 6

1. Antiseptic agents (triclosan) or local anesthetics (lidocaine) for symptomatic relief 6
2. Topical corticosteroids if antiseptics ineffective 3, 6
   • These achieve pain relief, reduce ulcer duration, and restore oral function 3
   • Note: Topical agents do not alter recurrence rates 3

Lifestyle Modifications

Advise patients to avoid: 6

• Hard, acidic, and salty foods
• Toothpastes containing sodium lauryl sulfate
• Alcohol and carbonated drinks

Second-Line: Systemic Therapy

Reserve for severe cases unresponsive to topical treatment: 3, 4, 6

• Colchicine: First-line systemic therapy for recurrent aphthous stomatitis and Behçet's disease 4, 6
• Oral corticosteroids (prednisolone): For severe major RAU refractory to topical agents 3, 6
• Pentoxifylline: Alternative systemic option 6
• Thalidomide: Most effective for refractory cases but limited by toxicity; use only when corticosteroids fail 3, 4

Treatment of Underlying Systemic Causes

When identified: 5, 4

• Nutritional deficiencies: Supplement iron, folate, or vitamin B12 5, 4
• Celiac disease: Gluten-free diet 4
• Inflammatory bowel disease: Optimize IBD-specific therapy 4
• Behçet's disease: Colchicine as first-line with topical agents 4

Critical Pitfalls to Avoid

• Never rely solely on topical treatments for persistent ulcers without establishing diagnosis—this delays identification of malignancy or systemic disease 2, 5
• Do not overlook systemic causes (blood disorders, HIV, autoimmune disease, IBD) in recurrent or severe cases 2, 5
• Inadequate biopsy technique (too small or superficial) misses critical diagnostic features 2, 5
• Every solitary chronic oral ulcer requires biopsy to exclude squamous cell carcinoma 4

Specialist Referral Indications

Refer to oral medicine specialist for: 2, 7

• Ulcers lasting >2 weeks
• No response to 1-2 weeks of appropriate treatment
• Recurrent, severe, or atypical presentations
• Need for biopsy or advanced diagnostic testing