Herpes Zoster Ophthalmicus Flashcards
What is herpes zoster ophthalmicus (HZO)?
A reactivation of the varicella-zoster virus in the ophthalmic division of the trigeminal nerve.
What causes herpes zoster ophthalmicus?
Reactivation of latent varicella-zoster virus (chickenpox) in the trigeminal ganglion.
What are the key symptoms of HZO?
Painful rash on the forehead, eyelid, or nose, along with redness, swelling, and potential vision changes.
What is Hutchinson’s sign?
The presence of vesicles on the tip or side of the nose, indicating nasociliary nerve involvement and a higher risk of ocular complications.
What is the pathophysiology of HZO?
Reactivation of the virus causes inflammation and damage to the skin, cornea, and other ocular structures.
What are the risk factors for HZO?
Increasing age, immunosuppression, stress, and previous chickenpox infection.
What are the stages of the rash in HZO?
Initially erythematous macules, followed by vesicles, pustules, and crusting over time.
What is the typical distribution of the rash in HZO?
It follows the dermatome of the ophthalmic branch of the trigeminal nerve, typically unilateral.
What are common ocular complications of HZO?
Keratitis, uveitis, conjunctivitis, scleritis, optic neuritis, and secondary glaucoma.
What is the significance of early treatment in HZO?
Early antiviral therapy reduces the risk of complications and severity of the disease.
What antivirals are used to treat HZO?
Oral aciclovir, valaciclovir, or famciclovir.
What is the typical duration of antiviral therapy in HZO?
Usually 7–10 days.
What is the role of topical corticosteroids in HZO?
To reduce inflammation in cases of keratitis or uveitis, prescribed by an ophthalmologist.
What is post-herpetic neuralgia (PHN)?
Persistent pain in the affected dermatome after the rash has resolved, a common complication of HZO.
What is the role of analgesia in HZO?
Pain relief with paracetamol, NSAIDs, or sometimes neuropathic pain agents like amitriptyline or gabapentin.
What are the differential diagnoses for HZO?
Herpes simplex virus (HSV) infection, cellulitis, contact dermatitis, and bacterial conjunctivitis.
What is the role of vaccination in preventing HZO?
The shingles vaccine (e.g., Zostavax, Shingrix) reduces the risk of developing HZO, especially in older adults.
What are the signs of corneal involvement in HZO?
Punctate epithelial keratitis, stromal keratitis, or corneal ulceration.
What investigations are needed for suspected HZO?
Diagnosis is usually clinical, but PCR or direct fluorescent antibody testing can confirm varicella-zoster virus.
What is the prognosis for HZO with treatment?
With prompt antiviral therapy, most patients recover, but some may have persistent visual or neurological complications.
What are systemic complications of HZO?
Post-herpetic neuralgia, cranial nerve palsies, and, rarely, encephalitis or stroke.
How does immunosuppression affect HZO?
It increases the risk of severe disease and complications, including prolonged viral shedding.
What is the role of artificial tears in HZO management?
To relieve dryness and irritation in cases of keratitis or reduced tear production.
How is uveitis associated with HZO treated?
Topical corticosteroids and cycloplegics, under the supervision of an ophthalmologist.
Why is ophthalmology referral important in HZO?
To manage ocular complications such as keratitis, uveitis, and secondary glaucoma, which can threaten vision.
