Otomycosis is caused by –
**Core Concept**
Otomycosis is a fungal infection of the external auditory canal, characterized by the overgrowth of fungi on the skin. This condition is more common in warm and humid climates, and can be caused by various species of fungi.
**Why the Correct Answer is Right**
The most common causative agent of otomycosis is **Aspergillus**. This fungus thrives in a warm and humid environment, and can infect individuals with compromised immune systems or those who use ear drops that contain antibiotics, which can disrupt the normal flora of the ear. Aspergillus produces enzymes that break down the skin's natural barriers, allowing it to penetrate and colonize the external auditory canal.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because while Candida can cause fungal infections, it is not the most common causative agent of otomycosis.
**Option B:** This option is incorrect because Pseudomonas is a bacterium, not a fungus, and is not associated with otomycosis.
**Option C:** This option is incorrect because Malassezia is a yeast-like fungus that is commonly associated with skin conditions such as dandruff, but is not a primary cause of otomycosis.
**Clinical Pearl / High-Yield Fact**
It's essential to note that otomycosis can be misdiagnosed as otitis externa, a bacterial infection of the ear canal. A definitive diagnosis requires a fungal culture or a potassium hydroxide (KOH) preparation of the affected tissue.
**Correct Answer: D. Aspergillus. Aspergillus**