Ulcers - oral
Red flags
- Ulceration persisting beyond 3 weeks without healing (malignancy red flag), associated systemic symptoms (fever, weight loss), and ulceration with signs of malignancy (induration, fixed/indurated edge, associated lymphadenopathy) warranting urgent specialist referral
Differential by mechanism
Recurrent/idiopathic: recurrent aphthous stomatitis (the most common cause, minor/major/herpetiform subtypes)
Infective: herpes simplex (primary gingivostomatitis or recurrent herpes labialis), hand-foot-mouth disease (coxsackievirus)
Systemic/inflammatory: Behcet disease, inflammatory bowel disease, coeliac disease, autoimmune bullous disease (pemphigus vulgaris often presents with oral ulceration first)
Malignancy: squamous cell carcinoma, particularly in a patient with tobacco/alcohol risk factors and a non-healing ulcer beyond 3 weeks
Drug-related: methotrexate, nicorandil
Focused history
- Duration (persistent beyond 3 weeks is the key red-flag threshold), number and recurrence pattern, pain, associated systemic symptoms (GI symptoms suggesting IBD/coeliac, genital ulcers suggesting Behcet)
- Risk factor screen: tobacco and alcohol use (oral squamous cell carcinoma risk), medication review (methotrexate, nicorandil), nutritional deficiency symptoms (iron, B12, folate - associated with recurrent aphthous stomatitis)
Focused examination
- Ulcer site, number, size, base appearance (clean vs indurated/necrotic), and induration (a concerning feature for malignancy) on direct inspection and palpation
- Cervical lymphadenopathy assessment (relevant to both infective and malignant causes); skin and genital examination if a systemic/autoimmune cause is suspected (Behcet, pemphigus)
Investigation strategy
- Most recurrent aphthous ulceration requires no investigation beyond a directed history; FBC, iron studies, B12, folate, and coeliac serology where recurrent ulceration suggests an underlying nutritional/malabsorptive cause
- Biopsy for any ulcer persisting beyond 3 weeks without clear cause, or with concerning features (induration, non-healing, risk factor history) to exclude malignancy
Management
- Recurrent aphthous stomatitis: topical corticosteroids for symptom control, correction of any identified nutritional deficiency; most cases are self-limiting and require reassurance plus symptomatic care alone
- HSV gingivostomatitis: aciclovir if presenting early/severe, otherwise supportive care
- Suspected malignancy: urgent biopsy and specialist (oral/maxillofacial or ENT) referral - do not treat empirically while a malignant ulcer risk remains unaddressed
Traps
Missing the 3-week rule - persistent oral ulceration beyond 3 weeks always needs biopsy to exclude malignancy, regardless of how benign it initially appeared
Attributing everything to "aphthous ulcers" - recurrent oral ulceration can be the presenting feature of coeliac disease, inflammatory bowel disease, or Behcet disease, and warrants a systemic screen if genuinely recurrent rather than a single self-limiting episode
Missing oral pemphigus - oral ulceration frequently precedes cutaneous blistering in pemphigus vulgaris by weeks to months, making early recognition important
Talk track
"Most mouth ulcers are simple and heal on their own, but because this one has been present for [duration], I want to make sure we're not missing anything else - I'd like to examine it closely and consider some blood tests, and if it hasn't healed by three weeks a biopsy would be the next step."
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