Mouth ulcers

History and examination

The three main points to inquire about when evaluating ulcers are site; number (single or multiple); and onset/behaviour (acute, persistent, or recurrent). Ulcers lasting >3/52 are of concern as they may be malignant; alternatively, they may be due to chronic infection.

On examining, as well as looking for the site and number of lesions, look at size; whether the lesion is flat or elevated; at whether the edge is flat or elevated and regular or irregular; and for any sign of bleeding. Also check for cervical/submandibular swelling. Mouth examination should be performed with dentures/dental appliances removed, and should go through the following stages:

  • Lips
  • Inner labial mucosa, upper and lower
  • Buccal mucosa, right and left
  • Gingivae
  • Floor of the mouth
  • Dorsum of the tongue
  • Ventral tongue/floor of the mouth
  • Both lateral borders of the tongue
  • Hard and soft palate

Also, palpate the floor of the mouth for induration. Ditto any lesions.

For causes, remember the mnemonic So Many Laws And Directives:

  • Systemic
  • Malignant
  • Local trauma (physical or chemical)
  • Aphthous
  • Drug-induced


Further subdivide by acronym BIGS:

  • Blood disorders
  • Infections
  • Gastrointestinal
  • Skin disorders

Blood disorders: Anaemia, leukaemia/myelodysplasia, neutropenia, hypereosinophilic syndrome

Infective: Mainly viral:

  • Herpes
  • Chicken pox/shingles
  • Infectious mononucleosis
  • CMV
  • Echoviruses/coxsackieviruses (hand, foot & mouth, herpangina)
  • HIV

Also – mycobacterium tuberculosis, mycoses (candida, histoplasmosis), leishmaniasis, Treponema pallidum, ‘others’.

Gastrointestinal: coeliac disease, IBD


  • Pemphigus and pemphigoid
  • Lichen planus
  • Erythema multiforme
  • Dermatitis herpetiformis
  • Linear IgA disease
  • Epidermolysis bullosa

Vasculitis (the author conveniently ignores the fact that this doesn’t fit in the acronym at all):

  • Lupus
  • Behcet’s
  • Wegener’s granulomatosis
  • Sweet syndrome
  • Reiter’s syndrome
  • Periarteritis nodosa

Traumatic ulcers

In the case of ulcers due to a sharp-edged/broken tooth, obviously the cause needs to be removed. However, these can also be helped by prescribing an antiseptic mouthwash (chlorhexidine) and a mild topical analgesic (benzydamine mouthwash or spray).

Aphthous ulcers

Check full blood count and haematinics. (Also consider checks for coeliac disease and inflammatory markers to look for systemic GI causes, and HIV if appropriate.)

Benzydamine can help with symptoms, but topical steroid application is needed to shorten duration (unfortunately not licenced for this purpose). Methods of application include:

  • Triamcinolone in Orabase: take 5 mm of ointment and apply to the ulcer. Avoid eating or drinking for 5 – 10 minutes afterwards.
  • Fluticasone nasal spray – spray on the ulcer two or three times. Avoid eating or drinking for 5 – 10 minutes afterwards.
  • Betamethasone sodium phosphate tablets, 500 mcg – dissolve one tablet in 10 – 15 ml water and rinse the area for 2 – 3 minutes.

All the above should be repeated 3 – 4 times daily for 5 – 7 days. This, by the way, can also help with recurrent aphthous ulcers caused by an underlying disorder. Other methods of application apparently exist, but the links to the references didn’t seem to be working. (From experience, I can say I’ve seen steroid inhaler recommended by one consultant for this purpose, to be squirted directly on the lesions.)

Recurrent ulcers can be an autoinflammatory condition; this differs from an autoimmune condition in that the flare-up of the immune system does not seem to be triggered by an autoantigen.

If multiple ulcers are associated with headache, fever, malaise, gingival swelling and lymphadenopathy, consider primary herpes stomatitis as a diagnosis (occurs primarily in the first three decades of life), or possibly PFAPA (periodic fever, aphthous stomatitis, pharyngitis, cervical adenitis). Treatment is with systemic antivirals (such as aciclovir) plus symptomatic treatment.

About Dr Sarah

I'm a GP with a husband and two young children.
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