Oral Candidiasis

§ overviewOverview

Superficial infection of oral mucosa by Candida species (mainly C. albicans), occurring when host defences or oral flora are disrupted.

§ icdICD Classification

ICD-10 B37.0

§ etiologyEtiology

• 01Candida albicans (85%)
• 02C. glabrata, C. tropicalis, C. krusei (increasingly, especially in immunocompromised and after azole use)

§ riskRisk Factors

• 01Extremes of age (neonates, elderly)
• 02Denture wear (denture stomatitis)
• 03Xerostomia (Sjögren's, drugs, radiotherapy)
• 04Broad-spectrum antibiotics
• 05Inhaled/systemic corticosteroids
• 06Diabetes mellitus (poorly controlled)
• 07HIV/AIDS, chemotherapy, transplant patients
• 08Iron / folate / vitamin B12 deficiency
• 09Smoking

§ geneticsGenetics & Molecular Biology

• 01Chronic mucocutaneous candidiasis — AIRE gene mutation (APECED syndrome)
• 02STAT1 gain-of-function mutations

§ epidemiologyEpidemiology

Carriage rate of Candida in oral cavity ~30–50% of healthy adults. Clinical candidiasis common in denture wearers, HIV patients (>90%), infants (~5% neonates).

§ pathogenesisPathogenesis

Candida transitions from commensal yeast to pathogenic hyphal form when local (xerostomia, denture, mucosal breach) or systemic (immunosuppression, antibiotics) balance is disturbed. Hyphae adhere via ALS proteins and invade epithelium; SAP proteases and phospholipases mediate tissue damage.

§ clinicalClinical Features

• 01Pseudomembranous (thrush): creamy white curd-like plaques that wipe off leaving erythematous or bleeding base — palate, buccal mucosa, tongue
• 02Erythematous (atrophic): red, painful mucosa; central papillary atrophy of dorsal tongue (median rhomboid glossitis is a form)
• 03Chronic hyperplastic (candidal leukoplakia): white plaque that does NOT wipe off — commissures of buccal mucosa, potentially malignant
• 04Denture stomatitis (Newton's types I–III): erythema of denture-bearing palate
• 05Angular cheilitis: cracked, erythematous fissures at oral commissures
• 06Chronic mucocutaneous candidiasis: persistent skin, nail and mucosal involvement in immunodeficient patients

§ signsSigns & Symptoms

• 01Burning, altered taste (bitter, metallic)
• 02Sore mouth, dysphagia
• 03Pain on denture wear
• 04Cracked lip corners

§ differentialDifferential Diagnosis

• 01Leukoplakia (does not wipe off)
• 02Lichen planus
• 03Chemical burn
• 04Milk residue (infants)
• 05Erythroplakia
• 06Geographic tongue
• 07Lupus
• 08Erythema multiforme

§ criteriaDiagnostic Criteria

• 01Clinical + microscopy (KOH mount showing budding yeasts and pseudohyphae) or culture on Sabouraud dextrose agar

§ histopathHistopathology

• 01PAS or Grocott's silver stain shows fungal hyphae penetrating parakeratotic epithelium
• 02Neutrophilic microabscesses in upper epithelium (Munro-like)
• 03Chronic hyperplastic form: hyperkeratosis, acanthosis, chronic inflammation; may show dysplasia

§ investigationsInvestigations

• 01KOH 10% wet mount — budding yeast and pseudohyphae
• 02Sabouraud dextrose agar culture with germ-tube test (C. albicans)
• 03Oral rinse / imprint culture (quantitative)
• 04Biopsy for chronic hyperplastic candidiasis
• 05Screen underlying disease: HIV, diabetes, immunodeficiency, haematinics

§ ihcIHC / Special Stains

• 01Not routinely required; PAS stain sufficient to demonstrate hyphae

§ whoWHO Classification

Classified by Lehner (1966), revised by Holmstrup & Axéll (1990): acute pseudomembranous, acute erythematous, chronic hyperplastic, chronic erythematous, Candida-associated (denture stomatitis, angular cheilitis, MRG).

§ classificationClassification

• 01Primary (confined to mouth/perioral tissues): pseudomembranous, erythematous, hyperplastic, Candida-associated
• 02Secondary: chronic mucocutaneous candidiasis with systemic disease

§ planTreatment Planning

• 01Identify and correct predisposing factors
• 02Topical antifungal for mild/localised disease
• 03Systemic antifungal for extensive/refractory disease
• 04Denture hygiene / replacement for denture stomatitis

§ treatmentTreatment

• 01Topical: nystatin oral suspension 100,000 IU/ml — swish & swallow 4× daily for 7–14 days
• 02Topical: miconazole oral gel 2% or clotrimazole troches 10 mg 5×/day
• 03Systemic: fluconazole 100–200 mg once daily 7–14 days (recurrent/immunocompromised)
• 04Itraconazole 200 mg/day or voriconazole for azole-resistant strains
• 05Denture stomatitis: soak denture in chlorhexidine 0.2% or sodium hypochlorite overnight, replace worn dentures
• 06Angular cheilitis: miconazole cream + hydrocortisone (Daktacort) to commissures

§ medicalMedical Management

• 01Nystatin, miconazole, clotrimazole (topical)
• 02Fluconazole, itraconazole, voriconazole (systemic)
• 03Amphotericin B for invasive/refractory disease

§ surgicalSurgical Management

• 01Excision of chronic hyperplastic candidiasis lesions if dysplasia present

§ complicationsComplications

• 01Oesophageal candidiasis (immunocompromised)
• 02Systemic candidaemia
• 03Malignant transformation of chronic hyperplastic candidiasis
• 04Azole resistance

§ recurrenceRecurrence Rate

Common if predisposing factors persist. Denture stomatitis relapses in >50% without denture replacement.

§ followupFollow-up Protocol

• 01Reassess at 2 weeks after starting treatment
• 02Investigate for underlying HIV/diabetes/immunodeficiency in recurrent disease

§ prognosisPrognosis

Excellent for acute forms in immunocompetent hosts; poorer for chronic mucocutaneous and hyperplastic types. ≈ 10% of chronic hyperplastic candidiasis develops dysplasia/SCC.

§ preventionPrevention

• 01Denture hygiene — remove at night, brush and soak
• 02Rinse mouth after inhaled steroid use
• 03Glycaemic control
• 04Prophylactic antifungals in HIV/chemotherapy

§ examKey Examination Points

• 01Wipes off?
• 02Denture-bearing area involvement?
• 03Commissures for angular cheilitis?
• 04Systemic disease clues?

§ revisionQuick Revision Summary

• 014 primary + 3 Candida-associated types
• 02Pseudomembranous wipes off; hyperplastic does not
• 03PAS stain shows hyphae
• 04Topical nystatin first line; fluconazole for refractory
• 05Always investigate underlying disease in recurrent cases

§ vivaBDS Viva Questions

• 01Classify oral candidiasis (Holmstrup–Axéll).
• 02How do you differentiate candidiasis from leukoplakia clinically?
• 03Describe the histopathological features.
• 04Name predisposing factors.
• 05First-line topical antifungal and dose.
• 06What is denture stomatitis and Newton's classification?
• 07Which form has malignant potential?
• 08Management of angular cheilitis.
• 09Role of KOH mount.
• 10Why does inhaled steroid cause candidiasis?

§ bdsBDS Professional Examination

• 01Classify oral candidiasis. Describe the clinical features, investigations and treatment of denture stomatitis (10 marks).
• 02Short note: Angular cheilitis.

§ fcpsFCPS Residency Questions

• 01Discuss chronic hyperplastic candidiasis as an oral potentially malignant disorder.
• 02Management of azole-resistant oral candidiasis in HIV patients.

§ pearlsClinical Pearls

• 01Wipes off = candidiasis; doesn't wipe off = biopsy.
• 02Chronic hyperplastic candidiasis on commissures — 10% risk of dysplasia.
• 03Recurrent candidiasis in an adult — screen for HIV and diabetes.

§ mnemonicsMnemonics

• 01Predisposing = ABCDE: Antibiotics, Broad immunosuppression, Corticosteroids, Diabetes, Extremes of age

§ readingSuggested Reading

• 01Samaranayake LP. Essential Microbiology for Dentistry, 5e.
• 02Williams D, Lewis M. Pathogenesis and treatment of oral candidosis. J Oral Microbiol 2011.

§ differentialDifferential Comparison

§ mcqsMCQs — Assessment (8)

§ relatedRelated Diseases

References

1. Neville BW. Oral & Maxillofacial Pathology, 4e
2. Holmstrup P, Axéll T. Acta Odontol Scand 1990
3. IDSA Clinical Practice Guidelines for Candidiasis 2016