Clinical Presentation of Cladosporium Infection
Cladosporium infections present most commonly as cutaneous or subcutaneous lesions in immunocompetent hosts, but cause severe invasive pulmonary disease with cavitary lesions, brain abscesses, and fungemia in profoundly immunocompromised patients.
Clinical Manifestations by Host Status
In Immunocompetent Patients
Cutaneous/Subcutaneous Disease:
- Elevated scaly suppurating lesions with sinus tract formation on extremities 1
- Ecthyma-like crusted lesions typically on hands or exposed areas 2
- Localized subcutaneous nodules without systemic symptoms
- These superficial infections respond well to local therapy or oral azoles
In Immunocompromised Patients
Invasive Pulmonary Disease (Most Common Severe Presentation):
- Cavitary pulmonary lesions during neutropenic nadir 3
- Fever and dry cough in setting of profound immunosuppression 4
- Multiple bilateral pulmonary infiltrates or abscesses 5, 3
- Occurs primarily in patients with:
- Active chemotherapy (especially during neutropenic periods)
- AIDS with low CD4 counts
- Post-COVID-19 syndrome with persistent immunosuppression
- Hematologic malignancies (mantle cell lymphoma, endometrial cancer)
Central Nervous System Disease:
- Multiple ring-enhancing brain abscesses involving basal ganglia, cerebellum, and cerebral hemispheres 6
- Presents with altered sensorium, aphasia, and hemiparesis
- Can occur following severe systemic infections (e.g., dengue) that compromise immunity
Fungemia:
- Documented in one case with mantle cell lymphoma undergoing chemotherapy 4
- Presents with fever and systemic signs of infection
- Requires prolonged blood culture incubation (slow-growing organism)
Key Diagnostic Clues
Clinical Context:
- Environmental exposure is critical: Patients homebound during neutropenia with excessive household mold exposure are at highest risk 3
- Timing: Symptoms typically emerge during neutropenic nadir (7-14 days post-chemotherapy)
Laboratory Findings:
- Markedly elevated serum 1,3-β-D-glucan (positive fungal biomarker) 4
- Negative galactomannan (distinguishes from Aspergillus) 4
- Blood cultures require prolonged incubation (slow-growing dematiaceous mold)
Imaging Characteristics:
- Pulmonary: Cavitary lesions, nodules, or consolidations
- CNS: Multiple thin-walled ring-enhancing lesions in multiple brain regions 6
Critical Pitfalls to Avoid
Misidentification as Cryptococcus: Histopathology may show yeast-like cells with narrow-based budding, mimicking cryptococcosis 5. Look carefully for sparse hyphae.
Dismissing as Contaminant: Cladosporium is ubiquitous and often considered a saprophyte. In immunocompromised patients with compatible clinical syndrome, treat as pathogenic until proven otherwise.
Inadequate Culture Duration: Standard incubation periods may miss this slow-growing organism. Extend culture incubation to at least 2 weeks in suspected cases.
Relying on Morphology Alone: Definitive identification requires molecular methods (MALDI-TOF with fungal database, ITS sequencing) 4, 5.
Clinical Algorithm for Recognition
Step 1: Identify high-risk patient (chemotherapy-induced neutropenia, AIDS, post-COVID immunosuppression)
Step 2: Recognize compatible syndrome:
- Pulmonary: Fever + cough + cavitary lesions during neutropenia
- CNS: Altered mental status + focal deficits + multiple ring-enhancing lesions
- Cutaneous: Suppurating nodules with sinuses (any immune status)
Step 3: Order appropriate diagnostics:
- Serum β-D-glucan (expect markedly elevated)
- Prolonged fungal cultures (minimum 2 weeks)
- Tissue biopsy with special stains for dematiaceous fungi
- Molecular identification if culture positive
Step 4: Assess environmental exposure history, particularly household mold exposure during immunosuppression
The rarity of invasive Cladosporium infections (only 5 previously reported cases of invasive disease worldwide before 2026) 4 means maintaining high clinical suspicion in the appropriate context is essential for timely diagnosis and treatment.