Oral ulcers can be a conundrum with a long list of differential diagnoses. Considering aetiology assists in understanding them.

Dr Amanda Phoon Nguyen, Oral Medicine Specialist

Dr Amanda Phoon Nguyen, Oral Medicine Specialist

An ulcer is defined as the loss of full thickness surface epithelium, as distinct from an area of erosion, where there is partial, but not full thickness loss of surface epithelium. Oral ulcers may form as a result of trauma including iatrogenic means such as chemotherapy and/or radiotherapy, from rupture of vesicles or bullae and other host-related factors.

A most useful approach is to determine if an ulcer is persistent. This is typically anything lasting over two weeks.

The differential diagnoses for a persistent localised ulcer include a chronic traumatic ulcer and its variant TUGSE (traumatic ulcerative granuloma with stromal eosinophilia), a major apthous ulcer, apthous-like ulcers, infective ulcers (e.g. deep fungal mycoses, tuberculosis or syphilis), or a neoplastic process.

Consider biopsy for all persistent, localised ulcers to exclude early squamous cell carcinoma. Differential diagnoses for generalised persistent oral ulceration include the above, vesiculobullous disorders, immune-mediated conditions (e.g. oral lichen planus), drug reactions, and rarer entities (e.g. Wegner’s granulomatosis, necrotising sialometaplasia, periarteritis nodosa).

Common medications which may cause oral ulcers as an adverse side effect include antihypertensives, anti-diabetics, NSAIDS, methotrexate and allopurinol. The list of possible implicated drugs is extensive.

Common oral ulcers that resolve within two weeks can result from acute trauma, and apthous ulcers. Other differentials include viral (e.g. herpes simplex and the Group A coxsackieviruses), erythema multiforme and plasma cell gingivostomatitis.

Causes of a traumatic acute ulcer are numerous, including mechanical, thermal, chemical and even electrical. Apthous ulcers may result from recurrent apthous stomatitis (RAS), haematinic deficiencies, celiac disease and Behcet’s syndrome. They may also present in conjunction with other syndromes such as periodic fever, aphthous stomatitis, pharyngitis, adenitis (PFAPA).

RAS apthae are recurrent, painful and typically start in childhood.  They tend to improve with age, and can occur in the minor, major and herpetiform forms. This condition is common, occurring in 25-60% of the population. The cause is not known, but a genetic predisposition is suggested.  They are typically multiple, ovoid or round, and covered by fibrin and surrounded by a pronounced red halo.

The hard palate and gingiva are rarely affected. Minor apthae are small, between 2-4mm, last seven to 10 days, and heal with no major scarring.  Major apthae are less common, have a crateriform appearance, can exceed one centimetre in diameter, take months to heal and may heal with scarring.

For management of these ulcers, predisposing and confounding factors should be corrected. Good oral hygiene is important. Chlorhexidine mouthwashes, topical and systemic corticosteroids and other steroid sparing agents may be considered.

Key messages

  • Oral ulceration has multiple differential diagnoses
  • Categorising the ulcers into acute or persistent forms can be helpful
  • Consider biopsy in all persistent, localised ulcers to exclude early squamous cell carcinoma

References available on request.

Questions? Contact the editor.

Author competing interests: nil

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