A 75-year old diabetic patient presents with severe ear pain and granulation tissue at external auditory canal with facial nerve involvement. The most likely diagnosis is:
**Core Concept**
The underlying condition being tested involves a severe infection of the external auditory canal, particularly in diabetic or immunocompromised patients. This condition is known as **malignant otitis externa**, which can lead to serious complications if not promptly treated. The **external auditory canal** and surrounding structures are involved.
**Why the Correct Answer is Right**
Malignant otitis externa is a **necrotizing infection** that typically affects diabetic or immunocompromised patients, causing severe pain and granulation tissue formation in the external auditory canal. The involvement of the **facial nerve** indicates a more severe infection that has spread beyond the canal. **Pseudomonas aeruginosa** is the most common causative organism.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it does not specify the condition.
**Option B:** Incorrect as it is not the most common cause of this clinical presentation.
**Option C:** Incorrect because, although it could be related, the description does not match the given clinical scenario.
**Option D:** Incorrect as it is not directly related to the symptoms described.
**Clinical Pearl / High-Yield Fact**
Malignant otitis externa is a medical emergency, especially in diabetic patients, requiring prompt **antibiotic treatment** and possibly **surgical debridement** to prevent further complications, such as cranial nerve involvement or intracranial spread.
**Correct Answer:** D. Malignant otitis externa.