**Question:** Malignant otitis externa is characterized by all except

A. Infection limited to the external auditory canal
B. Acute onset
C. Absence of neurological symptoms
D. Resolution with over-the-counter medications

**Core Concept:** Malignant otitis externa is a rare, severe form of outer ear infection caused by Pseudomonas aeruginosa or other gram-negative bacteria. It typically affects immunocompromised patients and can lead to intracranial extension and serious complications if not promptly diagnosed and treated.

**Why the Correct Answer is Right:** Malignant otitis externa is characterized by a progressive and destructive infection involving the external auditory canal, skull base, and sometimes the temporal bone. It is not limited to the external auditory canal (option A), as it can extend deep into the temporal bone and cause complications. The infection does not have an acute onset (option B), as it typically presents gradually. Malignant otitis externa does not occur in the absence of neurological symptoms (option C), as it can progress to involve the skull base and cause intracranial extension. Finally, malignant otitis externa cannot be resolved with over-the-counter medications (option D), as it requires prompt medical attention and targeted antibiotic therapy.

**Why Each Wrong Option is Incorrect:**

A. Infection limited to the external auditory canal: Malignant otitis externa can extend beyond the external auditory canal, making this option incorrect.
B. Acute onset: Malignant otitis externa typically presents gradually, so it is not characterized by an acute onset.
C. Absence of neurological symptoms: Malignant otitis externa can lead to intracranial extension and cause neurological symptoms, making this option incorrect.
D. Resolution with over-the-counter medications: Malignant otitis externa requires prompt medical attention, typically involving antibiotic therapy specific to the involved bacteria, making over-the-counter medications ineffective.

**Clinical Pearl:** Malignant otitis externa is a severe infection that should not be underestimated, as it can have serious complications if left untreated. In immunocompromised patients, a high index of suspicion is crucial for early diagnosis and appropriate management.