A 74-year-old woman comes to the office due to several days of right ear pain. This morning she had 2 episodes of dizziness and almost fell. The patient is currently taking trimethoprim-sulfamethoxazole for an uncomplicated urinary tract infection. She has had no subjective fever, vision loss, or headaches. Temperature is 37 C (98.6 F), blood pressure is 116/78 mm Hg, and pulse is 100/min. Ear examination reveals several erythematous vesicles in the right external auditory canal with no drainage. The tympanic membrane is visible and intact. There is mild right-sided facial droop. The rest of the physical examination is unremarkable. Which is the most likely cause of this patient's illness?

Question

A 74-year-old woman comes to the office due to several days of right ear pain.  This morning she had 2 episodes of dizziness and almost fell.  The patient is currently taking trimethoprim-sulfamethoxazole for an uncomplicated urinary tract infection.  She has had no subjective fever, vision loss, or headaches.  Temperature is 37 C (98.6 F), blood pressure is 116/78 mm Hg, and pulse is 100/min.  Ear examination reveals several erythematous vesicles in the right external auditory canal with no drainage.  The tympanic membrane is visible and intact.  There is mild right-sided facial droop.  The rest of the physical examination is unremarkable.  Which is the most likely cause of this patient's illness?

Quizplus · Accepted Answer

This patient with a vesicular ear rash and facial droop likely has herpes zoster oticus (Ramsay Hunt syndrome). This condition is caused by the reactivation of varicella zoster virus from the geniculate ganglion, disrupting motors fibers of cranial nerve VII (facial nerve) with subsequent spread to cranial nerve VIII (vestibulocochlear nerve). The 2 defining manifestations are a painful, erythematous, vesicular rash on the auditory canal or auricle and ipsilateral facial paralysis. Many patients also develop vestibular (eg, vertigo, nausea/vomiting), hearing, and taste disturbances, but systemic symptoms (eg, fever) are rare (<20%). Treatment with an antiviral medication (eg, valacyclovir) may speed resolution and limit adverse outcomes. However, many patients are left with residual facial muscle weakness or paralysis. (Choice A) Lyme disease is caused by Borrelia burgdorferi, and early disseminated Lyme disease can be associated with facial nerve palsy (~8% of cases). However, the rash of Lyme disease is erythema migrans, a slowly spreading erythematous lesion with central clearing. Vesicular lesions would be atypical. (Choice B) The reactivation of herpes simplex virus (HSV) type 1 is the leading cause of Bell palsy (acute-onset, unilateral facial paralysis). However, HSV usually causes vesicular lesions on the oral mucosa, not the auditory canal. The presence of ear lesions makes varicella zoster reactivation far more likely. (Choice C) Pseudomonas aeruginosa is the leading cause of acute external otitis, which is common in swimmers and usually marked by ear itching and pain. Physical examination typically reveals thick, purulent discharge from the ear canal (unlike this patient). Vesicular lesions are not a common feature of this illness. (Choice D) Although Stevens-Johnson syndrome is frequently associated with the use of antibacterial sulfonamides (eg, trimethoprim-sulfamethoxazole), this illness is usually marked by high fever; a flu-like prodrome; hemorrhagic oral/ocular lesions; and an erythematous, macular rash with a purpuric center. Educational objective: Herpes zoster oticus (Ramsay Hunt syndrome) is caused by the reactivation of varicella zoster virus in the geniculate ganglion, disrupting cranial nerve VII motor fibers, with subsequent spread to cranial nerve VIII. Primary manifestations include a painful, erythematous, vesicular rash on the auditory canal or auricle and ipsilateral facial paralysis. References: Ramsay Hunt syndrome. (http://www.ncbi.nlm.nih.gov/pubmed/11459884)

A 74-Year-Old Woman Comes to the Office Due to Several