Mouth Ulcers

Differential Diagnosis

Common Diagnoses

Occasional Diagnoses

Rare Diagnoses

  • Carcinoma: Squamous Cell, Salivary Gland
  • Autoimmune: behçet’s Syndrome, Pemphigoid, Pemphigus, Bullous Erythema Multiforme
  • Syphilitic Chancre or Gumma
  • Leukaemia, Agranulocytosis (May be Iatrogenic)
  • Tuberculosis
  • HIV Infection

Ready Reckoner

Key distinguishing features of the most common diagnoses

TraumaRAUANUGThrushDeficiency States
Usually in CropsNoYesPossibleYesYes
White Buccal PlaquesNoNoNoYesNo
Bleeding GumsNoNoYesNoNo
Mucosal PallorNoNoNoNoYes

Possible Investigations

Likely:FBC, ferritin.

Possible:Urinalysis, vitamin B12 and folate, coeliac screen.

Small Print:Swab, autoantibody screen, syphilis and HIV serology, biopsy.

  • FBC: Essential basic investigation for anaemia and rarer blood dyscrasias. Ferritin for iron deficiency.
  • Urinalysis: Check for glycosuria. Underlying diabetes may predispose to infective causes (especially Candida).
  • Vitamin B12 and folate: To establish underlying vitamin deficiency (especially if MCV raised).
  • Coeliac screen: Anti-endomysial and anti-gliadin antibodies suggest coeliac disease if positive.
  • Swab: May help confirm doubtful diagnosis of ANUG – confirms presence of Vincent’s organisms.
  • Autoantibody screens and HLA tests may be useful if autoimmune causes are suspected.
  • Syphilis or HIV serology: If syphilis or HIV are suspected.
  • Biopsy: Required in persistent ulcer of uncertain aetiology (secondary care investigation).

Top Tips

  • Consider vitamin or iron deficiency, especially if the patient has glossitis and angular cheilitis as well as oral ulceration.
  • The patient with sore, ulcerated gums and foul halitosis has ANUG; the smell is sometimes apparent as soon as the patient walks in.
  • Patients with RAU often believe they are suffering from a vitamin deficiency; in fact, this is rarely the case, but be sure to broach this with them and consider a blood test as this may reinforce your reassurance.
  • Enquire about skin problems elsewhere in an obscure case – this may give a clue to the precise diagnosis.
  • Faucial ulceration and petechial haemorrhages of the soft palate and pharynx are likely to be caused by glandular fever.

Red Flags

  • A solitary, persistent and often painless ulcer could be malignant – especially in smokers. Refer urgently to the oral surgeon for biopsy.
  • Ask about bowel function – diarrhoea, abdominal pain and bloodstained stools with mucus suggest associated inflammatory bowel disease.
  • Don’t forget to enquire about medication – blood dyscrasias are a rare but significant side effect of some treatments (e.g. carbimazole), and oral ulceration may be the first sign.
  • Oral candidiasis is common in the debilitated and those with dentures, but much less so in the otherwise apparently fit. In the latter cases consider underlying problems such as immunosuppression or diabetes.
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