Oral Fungal Infections

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management

Definition

Oral fungal infections refer to fungal overgrowth within the oral cavity, most commonly caused by Candida species, leading to mucosal irritation and discomfort.

Aetiology

  • Candida albicans (most common): opportunistic yeast infection.
  • Other Candida species: C. glabrata, C. tropicalis, C. krusei (more common in immunocompromised individuals).
  • Fungal overgrowth: secondary to altered oral flora, immunosuppression, or antibiotic use.

Pathophysiology

  • Candida species are part of normal oral flora but can proliferate under favourable conditions.
  • Immunosuppression, antibiotic use, or disrupted mucosal barriers lead to fungal overgrowth and infection.
  • Inflammatory response results in erythema, pseudomembranous plaques, and discomfort.

Risk Factors

  • Immunosuppression (HIV/AIDS, chemotherapy, corticosteroid use).
  • Recent broad spectrum antibiotic use.
  • Poor oral hygiene or use of dentures.
  • Diabetes mellitus.
  • Smoking.
  • Dry mouth (xerostomia).

Signs and Symptoms

  • Pseudomembranous candidiasis (thrush): white curd-like plaques that can be wiped off, leaving an erythematous base.
  • Erythematous candidiasis: red, inflamed mucosa, often associated with burning sensation.
  • Angular cheilitis: painful cracks at the corners of the mouth.
  • Denture associated stomatitis: erythema under dentures.
  • Dysphagia: in severe or oesophageal involvement.

Investigations

  • Clinical diagnosis: based on characteristic oral lesions.
  • Oral swab and microscopy: potassium hydroxide (KOH) preparation to detect fungal elements.
  • Fungal culture: if diagnosis is uncertain or resistant infection suspected.
  • Blood glucose levels: to assess for underlying diabetes.
  • HIV testing: if immunodeficiency is suspected.

Management

1. Antifungal Therapy:

  • Topical antifungals: nystatin suspension or miconazole gel (first line for mild cases).
  • Systemic antifungals: fluconazole for moderate to severe or recurrent infections.
  • Alternative agents: itraconazole or amphotericin B for resistant cases.

2. Address Underlying Causes:

  • Optimise diabetes control.
  • Reduce unnecessary antibiotic use.
  • Improve denture hygiene (cleaning and removal at night).
  • Encourage smoking cessation.

3. Referral:

  • Dental specialist: for denture related infections.
  • Infectious diseases: for recurrent or refractory cases in immunocompromised patients.
  • Endocrinology: if underlying diabetes requires specialist management.
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