Clinical Manifestations and Diagnostic Features of Fungal Sinusitis
Fungal sinusitis presents in three distinct clinical forms—allergic fungal sinusitis, fungus ball, and invasive fungal sinusitis—each with unique presentations that guide diagnosis and determine prognosis. 1
Allergic Fungal Sinusitis (Non-invasive)
Patient Profile and Presentation:
- Occurs exclusively in immunocompetent patients with atopic disease, typically presenting with nasal polyps and chronic nasal congestion and obstruction 1
- Symptoms are longstanding and chronic in nature 1
- In children, unilateral disease with facial deformity may be present 1
- Patients often have positive skin testing to fungal organisms and elevated total serum IgE levels 1
Characteristic Physical Findings:
- Sinus contents have a distinctive "peanut butter-like consistency" 1
- Dramatic encroachment on adjacent structures (orbit, central nervous system) due to expansion of intrasinal contents, though true invasion rarely occurs 1
- Nasal polyps are typically present 1
Histologic Features:
- Fungal elements with abundant mucinous material on examination 1
- Eosinophilic mucin is a hallmark finding 1
- Represents an immunologically mediated reaction to inhaled fungal spores 1
Geographic Distribution:
- Most common in the south, southwest, and western United States 1
Common Causative Organisms:
- Bipolaris, Curvularia, Aspergillus, and Dreschlera species are most frequent 1
Fungus Ball (Non-invasive)
Location and Laterality:
Clinical Presentation:
- Chronic symptoms including nasal obstruction and headache 1
- Pressure necrosis may occur as the mass impinges on surrounding structures, but invasion is rare 1
Distinguishing Histologic Features:
- Dense accumulations of hyphae in concentric layers forming the fungus ball 1
- Eosinophilic mucin is NOT present—this is the key differentiator from allergic fungal sinusitis 1
Invasive Fungal Sinusitis (Fulminant)
High-Risk Patient Populations:
- Immunocompromised patients including:
- Diabetic patients 1
- Patients with leukemia or solid malignancies who are febrile and neutropenic (especially those on broad-spectrum antimicrobials) 1
- Patients receiving high-dose steroid therapy (connective tissue disease, transplant recipients) 1
- Patients with severe impairment of cell-mediated immunity (transplant recipients, congenital or acquired T-cell immunodeficiencies) 1
Clinical Presentation (Life-Threatening):
- Fever, headache, epistaxis, and mental status changes are common signs 1
- Insensate nasal ulcers may be present 1
- This represents a fulminant disseminated disease formerly called mucormycosis 1
Critical Management Implications:
- This form carries significant morbidity and mortality 2
- Requires aggressive debridement and systemic antifungal therapy 1
- Early diagnosis is essential for favorable outcomes 2
Diagnostic Approach
Clinical Diagnosis:
- Based on combination of clinical history, physical examination, imaging studies, and/or laboratory tests 1
Imaging:
- CT scanning is the imaging technique of choice, demonstrating abnormalities in both the ostiomeatal complex and sinus cavities 1
- In allergic fungal sinusitis, CT shows sinus mucosal hypertrophy and often hyperattenuation of sinus contents 3
Laboratory and Histopathology:
- Surgical histopathology with or without positive fungal culture establishes definitive diagnosis 3
- Nasal cytology may be useful in evaluating associated conditions 1
- In allergic fungal sinusitis, histopathology shows extramucosal allergic mucin staining positive for scattered fungal hyphae and eosinophilic-lymphocytic inflammation 3
Common Pitfall: The clinical overlap between fungal sinusitis and other forms of rhinosinusitis necessitates imaging and histologic confirmation—do not rely on symptoms alone, as they are nonspecific 1