What is the etiology of esophageal candidiasis?

Etiology of Esophageal Candidiasis

Esophageal candidiasis is primarily caused by Candida albicans and is strongly associated with immune suppression, particularly in patients with CD4+ T lymphocyte counts below 200 cells/µL. 1

Causative Organisms

• Primary pathogen: Candida albicans (most common cause) 1
• Secondary pathogens: Non-albicans Candida species, particularly C. glabrata, which emerge especially in patients with:
  • Previous fluconazole exposure
  • Repeated and long-term azole treatment
  • Advanced immunosuppression 1

Risk Factors

Immunological Factors

• HIV/AIDS (particularly CD4+ count <200 cells/µL)
• Immunosuppressive therapy
• Malignancy (especially hematologic)
• Organ transplantation

Medication-Related Factors

• Recent antibiotic use (disrupts normal flora)
• Local or systemic steroid use
• Proton pump inhibitor use 2
• Previous exposure to fluconazole or other azoles 1

Patient-Specific Factors

• Advanced age
• Chronic alcohol use
• Chronic kidney disease
• Diabetes mellitus 2

Mechanical/Structural Factors

• Esophageal motility disorders leading to stasis 2
• Achalasia
• Scleroderma 3

Pathophysiological Mechanism

1. Normal colonization: Candida species are common commensals on mucosal surfaces in healthy persons 1

2. Transition to pathogen: Under certain conditions (immunosuppression, antibiotic use, etc.), Candida transitions from commensal to pathogen

3. Mucosal invasion: Candida invades the esophageal mucosa, forming characteristic white plaques and pseudohyphae that invade mucosal cells 3

4. Inflammatory response: Host immune response to invasion causes symptoms including odynophagia and dysphagia

5. Potential complications: In severe cases, complications may include:

   • Esophageal strictures through chronic inflammation
   • Tissue damage and fibrosis
   • Scarring and narrowing of the esophageal lumen 4
   • Rarely: necrotizing esophageal candidiasis, fistula formation, and sepsis 3

Clinical Significance

Esophageal candidiasis serves as an important clinical marker:

• Recognized as an indicator of immune suppression 1
• In HIV patients, it's considered an AIDS-defining illness 5
• The introduction of antiretroviral therapy has led to a dramatic decline in prevalence among HIV patients 1

Diagnostic Considerations

Diagnosis requires:

• Endoscopic visualization of white plaques
• Histopathologic demonstration of characteristic Candida yeast forms in tissue
• Culture confirmation of Candida species 1

Understanding the etiology of esophageal candidiasis is crucial for appropriate management with systemic antifungal therapy, typically fluconazole (200-400 mg daily for 14-21 days) 2, 6.