RHS, also known as Herpes Zoster Oticus, is caused by the reactivation of the varicella-zoster virus (VZV) in the geniculate ganglion of the facial nerve.
It typically occurs in older adults or individuals with compromised immune systems.
Diagnosis:
History (Hx):
Sudden onset of painful, vesicular rash in the ear canal or on the auricle.
Facial paralysis or weakness on the same side as the rash.
Possible hearing loss, tinnitus, vertigo, or balance disturbances.
Examination (Ex):
Inspection of the ear for vesicular lesions.
Assessment of facial nerve function (facial droop, inability to close the eye, loss of forehead creases, etc.).
Evaluation for auditory and vestibular symptoms.
Investigations (Ix):
PCR testing of vesicle fluid or blood for VZV.
Audiometry if hearing loss is suspected.
MRI or CT scan may be needed to rule out other causes of facial paralysis.
Differential Diagnosis (DDx):
Bell’s Palsy (idiopathic facial nerve paralysis).
Middle ear infections.
Stroke.
Management (Mx):
Medications:
Antivirals: Acyclovir (Zovirax), Valacyclovir (Valtrex), or Famciclovir (Famvir) to reduce viral replication.
Corticosteroids: Prednisone to reduce inflammation and improve outcomes.
Analgesics: Pain relief for herpetic pain and post-herpetic neuralgia.
Supportive Care:
Eye care to prevent corneal damage (artificial tears, eye patch).
Physical therapy for facial muscles if paralysis is prolonged.
Postherpetic Neuralgia (PHN)
Cause:
PHN is a complication of shingles (Herpes Zoster), where pain persists in the area of the shingles rash long after the rash has healed.
It’s more common in older individuals and those with severe shingles.
Diagnosis:
History (Hx):
A history of shingles in the same location as the persistent pain.
Descriptions of pain type (burning, stabbing, etc.) and triggers.
Examination (Ex):
Inspect previously affected areas for post-inflammatory changes.
Sensory examination to check for altered sensation.
Investigations (Ix):
Usually a clinical diagnosis based on history and physical examination.
Rarely, skin biopsy or nerve conduction studies if the diagnosis is in doubt.
Differential Diagnosis (DDx):
Trigeminal neuralgia.
Diabetic neuropathy.
Complex regional pain syndrome.
Management (Mx):
Medications:
Gabapentanoid Anticonvulsants: Gabapentin (Neurontin) or Pregabalin (Lyrica) for neuropathic pain.
Tricyclic Antidepressants: Amitriptyline, Nortriptyline for neuropathic pain.
SNRI Antidepressants: Duloxetine for neuropathic pain.
Patient education about the nature of the condition.
Physical therapy or acupuncture may provide relief for some patients.
Patient education, close follow-up, and addressing comorbid conditions that might exacerbate symptoms (like stress or poor sleep) are important aspects of care.
