A 10-year-old boy is brought to the office due to an earache and droopy face. His mother reports that the patient has had right ear pain for the past 3 days without any fever or hearing loss. She instilled over-the-counter ear wax removal drops but there was no symptom relief. Today, she noticed that his face appeared lopsided when he smiled. The family recently immigrated to the United States, and the patient has had episodes of viral illnesses in the past. He takes no other medications. Temperature is 37 C (98.6 F). The patient has difficulty closing the right eye and has a right-sided facial droop. The pupils are normal, and there is no nystagmus. Right otoscopy shows crusted eruptions in the external auditory meatus. Which of the following is the most likely cause of this patient's current condition?
Show Explanatory Sources
This patient has the classic triad of herpes zoster oticus (ie, Ramsay Hunt syndrome):
Herpes zoster oticus is a manifestation of latent varicella-zoster virus (VZV) reactivation. Primary VZV infection (chickenpox) presents with a diffuse, vesicular rash associated with fever, malaise, and pharyngitis. The virus then migrates via sensory nerves to cranial nerve and dorsal spinal ganglia, where it lies dormant for years. Reactivation of the virus typically occurs in a single ganglion and causes a painful, vesicular rash in a dermatomal distribution; over time the lesions crust. Reactivation occurs commonly in adults, and can rarely occur in children, either after primary infection, vaccination, or maternal infection during pregnancy.
Herpes zoster oticus is caused by reactivation of latent VZV in the geniculate ganglion, disrupting facial nerve function. A vesicular rash in the EAC, which is innervated by the facial nerve, is classic. Subsequent spread to the vestibulocochlear nerve (CN VIII) can lead to auditory (eg, hearing loss, hyperacusis, tinnitus) and vestibular (eg, vertigo, nausea/vomiting) disturbances. Treatment is with corticosteroids and antiviral medications. Early initiation (<3 days) is associated with improved recovery of facial nerve function; however, even with treatment many patients have residual facial weakness. As in all patients with facial nerve paralysis, protection of the eye on the paralyzed side of the face (eg, artificial tears, lubricating ointment) is of paramount importance.
(Choice A) An allergy to ototopically administered medications could cause pain and a rash localized to the EAC. However, it would not cause facial weakness.
(Choice B) Fungal otitis externa occurs most commonly after treatment for acute otitis externa. It would not cause facial weakness; examination of the EAC would show whitish fungal debris with fruiting bodies or spores.
(Choice C) Necrotizing (malignant) otitis externa is usually caused by Pseudomonas and can present with severe ear pain and cranial neuropathies. However, it typically presents in elderly, immunocompromised (eg, poorly controlled diabetes) patients; physical examination typically shows granulation tissue in the EAC rather than a vesicular rash.
(Choice D) Pneumococcus can cause acute mastoiditis, which can present with severe ear pain and lead to facial nerve palsy. However, patients also have fever, mastoid process inflammation with displacement of the auricle, and no vesicular rash.
Educational objective:
The classic triad of herpes zoster oticus (ie, Ramsay Hunt syndrome) includes severe ear pain, ipsilateral facial paralysis, and a vesicular rash in the external auditory canal.