Oral Thrush (oral candidiasis)

Introduction

Oral Thrush (Candidiasis) is a clinical infection of mucous membranes due to the fungus species Candida.
Candida albicans is the most frequently isolated strain.

Classification of oral thrush

  1. Acute oral candidasis
  2. Chronic oral candidasis
  3. Denture association candidasis/ denture stomatitis

Pathogenesis/aetiology of oral thrush

  • Immunosupression results in the Candida albicans (a normal oral commensal) becoming virulent
  • It invades and proliferates in superficial epithelium
  • Results in a thick plaque which is oedematous and not easily rubbed off

Symptoms and clinical features of oral thrush

  • A creamy/whitish, soft and friable slough located on the soft tissues of the oral cavity: tongue, palate, cheek, pharynx
  • May be asymptomatic, or painful, with difficulty in swallowing

Predisposing factors

  1. Denture wearing
  2. Reduced salivation (e.g. drug induced)
  3. Antibiotic therapy (especially broad spectrum)
  4. Poorly controlled diabetes mellitus
  5. Steroid therapy (chronic)
  6. Salivary gland damage (e.g. post radiation)
  7. Malnutrition
  8. HIV infection
  9. Leukaemia
  10. Iron, vitamin B, folic acid deficiency and
  11. Agranulocytosis

Investigations

  • Smear of the affected region and Gram staining or PAS with or without potassiumvhydroxide to demonstrate hyphae
  • Swab sample for microscopy, culture and sensitivity
  • Biopsy and histopathologic examination
  • Identify predisposing factors (including immunosuppresion)
  • Define extent of involvement

Treatment for oral thrush

Non-drug treatment

  1. Manage any underlying predisposing factors
  2. Replace worn dentures
  3. Proper counselling of patients as to use of dentures
  4. Diet modification and improvement
  5. Chlorhexidine mouthwash three times daily for 1-2 weeks

Drug treatment

A. Topical anti-fungal medication:

i. Nystatin suspension

  • Adult: 100,000 units/mL 4 times daily, after food (usually for 7 days). Continue for 48 hours after lesions have resolved
  • Child
    • 1 month 18 years, prophylaxis and treatment: 100,000 units 6 hourly after food for 7 days. Continue for 48 hours after lesions have healed
    • Immunocompromised children: 500,000 units 6 hourly for 7 days

Or:

ii. Miconazole oral gel 2%

  • Adult: place 5-10 mL in the mouth after food and retain near lesions 4 times daily
  • Child
    • under 2 years: 2.5 mL twice daily;
    • 2 – 6:¬†years: 5 mL twice daily;
    • 6 – 12 years: 5 mL 4 times daily;
    • 12-18 years: 5-10mL. 4 times daily.
    • Leave in the mouth after food and retain near lesions.

B. Systemic antifungal drugs

Some patients may require systemic
antimicrobial medicines
i. Fluconazole

  • Adult: 50 mg orally daily for 7-14 days
  • Child: 3-6mg/kg on the first day, then 3mg/kg daily
    • For neonates up to 2 weeks old: administer every 72 hours;
    • 2 – 4 weeks old: administer every 48 hours