15th July 2023

Diseases of the Mouth

Primary Oral Disease

Recurrent Aphthous Stomatitis (RAS)

RAS, also known as canker sores, is a common condition resulting in recurrent episodes of painful oral ulcers. It is important to consider other differentials which may be causing oral ulcers (e.g., Behçet’s disease, IBD, HIV, coeliac disease) before coming to a diagnosis of RAS.

Oral Squamous Cell Carcinoma (SCC)

SSC is responsible for the majority of tumours found in the mouth. Certain pre-cancerous lesions can predispose to SSC, such as leukoplakia, erythroplakia and lichen planus. Risk factors are tobacco (including oral tobacco products), excess alcohol, HPV (type 16), obesity, age, male sex, and poor nutrition.

Persistent unexplained oral ulcers or lumps should be referred for biopsy to rule out SCC.

Other Primary Oral Diseases

Geographic tongue ― recurrent idiopathic inflammatory disorder, which results in glossitis and patches of depapillation.

Black hairy tongue ― a benign condition which can be seen in smokers, those with poor oral hygiene and some antibiotics.

Leukoplakia ― white patches on the oral mucosa, which is very common. In some patients this may progress to SCC. This is not to be confused with oral hairy leukoplakia (caused by EBV), which is almost entirely seen in patients with HIV.

Erythroplakia ― presents as red patches in the oral mucosa. Erythroplakia is also a premalignant lesion with a high risk of progression to SCC. Surgical excision is a common treatment.

Secondary Oral Disease

Oral manifestations secondary to systemic diseases are often tested in the MRCP examinations. Some of the more common oral manifestations that are tested are summarised below (table 1).

Table 1: Secondary oral manifestations of systemic conditions

Gingival Hypertrophy and Macroglossia

The causes of gingival hypertrophy and macroglossia are frequently tested in the MRCP examinations. Causes of each are summarised below.

Gingival hypertrophy:

• Inflammatory enlargement
  • Periodontal disease and poor dentition
• Drugs:
  • Anticonvulsants e.g. phenytoin, lamotrigine
  • Calcium-channel blockers (nifedipine in particular)
  • Ciclosporin
• Neoplastic
  • Leukaemia – particularly Acute Myeloblastic Leukaemia (AML)
• Infiltrative
  • Granulomatosis with polyangiitis, sarcoidosis, amyloidosis
• Pregnancy
• Scurvy

Macroglossia

• Inherited
  • Down syndrome
  • Neurofibromatosis 1
  • Mucopolysaccharidosis
  • Glycogen storage disorders
• Acquired
  • Endocrine
    • Acromegaly
    • Hypothyroidism
  • Haematological
    • Amyloidosis
    • Lymphomas
    • Multiple Myeloma
  • Angioedema
  • Carcinoma

Oral Flora

The healthy oral cavity is polymicrobial and home to aerobic and anaerobic bacteria. As such, human bites resulting in skin and soft tissue infection are often polymicrobial in origin. This requires treatment with a broad-spectrum antibiotic such as co-amoxiclav. Transmission of blood-borne viruses such as HIV, hepatitis B and C can also occur if there has been blood exposure from a human bite.

Cat and dog bites, on the other hand, often isolate Pasteurella species. Infected cats may result in infection with Bartonella henselae, which causes ‘cat-scratch disease’ – a disease characterised by localised, painful lymphadenopathy.