## Fungal Corneal Ulcer — Clinical Presentation & Management ### Key Distinguishing Features of Fungal vs. Bacterial Ulcers **Key Point:** Fungal corneal ulcers classically present with **minimal, mucoid discharge** and **slow, indolent progression**, NOT copious purulent discharge. This is a cardinal clinical differentiator. | Feature | Bacterial Ulcer | Fungal Ulcer | |---------|-----------------|---------------| | Onset | Rapid (24–48 hrs) | Insidious (days to weeks) | | Discharge | Copious, purulent | Minimal, mucoid | | Border | Well-demarcated | Feathery, indistinct | | Satellite lesions | Rare | Common | | Hypopyon | Frequent | Uncommon | | Response to antibiotics | Good | Poor | ### Epidemiology & Risk Factors **High-Yield:** In India, **Aspergillus** and **Fusarium** are the most common fungal pathogens, with regional variation. Trauma (especially vegetative matter) is the leading risk factor in agricultural populations. **Key Point:** Prolonged or inappropriate topical corticosteroid use is a major risk factor — steroids suppress local immunity and promote fungal proliferation. ### Microbiology & Diagnosis - **Gram stain:** Negative for bacteria; KOH mount reveals septate hyphae (Aspergillus, Fusarium) or yeast forms - **Culture:** Sabouraud dextrose agar (SDA) at 25–37°C - **Confocal microscopy:** Can visualize fungal elements in vivo ### Treatment Approach **Clinical Pearl:** Topical antifungals (natamycin 5%, voriconazole 1%, amphotericin B) are first-line. Natamycin is preferred for Aspergillus; voriconazole for Fusarium and Candida. **Warning:** Systemic antifungals (fluconazole, voriconazole) have poor corneal penetration and are reserved for severe or scleritis-associated cases. ### Why Option 2 Is Incorrect Fungal ulcers are **characteristically indolent** with **minimal discharge** — this is a key clinical clue that distinguishes them from bacterial ulcers, which present with copious purulent drainage and rapid spread. The slow, smoldering course and paucity of discharge often lead to delayed diagnosis.
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