Herpes Zoster (Shingles) Can Cause Severe Problems when it Causes the Eye to be Infected
Herpes zoster ophthalmicus is an infection of the eye caused by varicella zoster virus. Herpes zoster ophthalmicus is the ocular involvement of an overall infection termed herpes zoster, commonly called shingles. Varicella zoster is the same virus that causes chicken pox. Once people are infected with this virus, usually by chicken pox as a child, it remains within the body in a dormant stage in the sensory ganglion (nerve roots). It is estimated that 95% of all adults harbor this virus and are therefore at risk for shingles. The risk of obtaining a herpes zoster infection during one’s lifetime is estimated at 10-20%. Estimates are that in the U.S. alone each year there are one million cases of herpes zoster.
Reactivation of the Varicella Zoster Virus causes Shingles (Herpes Zoster)
The varicella zoster virus can remain in the dormant stage forever or for decades but can be reactivated in some people. Reactivation of the virus is caused by a decreased immune system that can be caused by aging, HIV, high stress levels or illness. When the virus reactivates it usually spreads to the skin causing a severe rash called herpes zoster (shingles). If the varicella zoster virus spreads down the first division of the trigeminal nerve it is called herpes zoster ophthalmicus. If the forehead or nose becomes infected, the eye often becomes infected on the same side as the skin involvement. The incidence of ocular involvement of all shingles cases is estimated to be as high as 25%.
Signs and Symptoms of Herpes Zoster Ophthalmicus
The shingles rash can be found on the back or midsection of the body, the arms, legs and neck. If there is a rash on the face during a shingles infection then it is possible that there will be herpes zoster ophthalmicus. Often the skin of the forehead and sometimes the tip of the nose are covered with small, extremely painful, red blisters. If there are sores on the tip of the nose it is highly likely that there is or will be Infection of the eye that causes pain, redness, light sensitivity and eyelid swelling.
Ocular involvement is complex and can create many different eye problems including:
Eyelid sores with scar tissue creating future complications.
Conjunctiva swelling (edema) and possible secondary infection within the first two weeks.
Sclera atrophy long after the disease heals.
Cornea can become inflamed/infected with several types of keratitis. Some cornea problems occur in the first few days of the herpes zoster ophthalmicus infection and others are not apparent for months later causing potential scarring and permanent loss of vision.
Anterior chamber of the eye can become inflamed and a uveitis/iritis which can create scarring and lead to glaucoma weeks to years later.
Treatment of Herpes Zoster
Oral antiviral medicine is used to treat shingles. The three medicines are Acyclovir (Zovirax), valacyclovir (Valtrex, GlaxoSmithKline) and Famciclovir (Famvir, Novartis). All three of these are available generically. In their prescribed dosages they are all relatively equal in therapeutic efficacy.
Dosage for treatment of Herpes Zoster and Herpes Zoster Ophthalmicus:
Acyclovir 800mg 5 times per day for 7-10 days
Valacyclovir 1,000mg 3 times per day for 7-10 days
Famciclovir 500mg 3 times per day for 7-10 days
All these medicines have a very good safety profile and in fact are only activated by the virus not by normal cells. The medicine rapidly and effectively stops the virus from reproducing. The drugs are only minimally involved with normal cells and therefore are very safe. The only exception to this is patients that have a reduced kidney function because these antiviral drugs are eliminated via urine. Consultation with a kidney specialist or urologist may be needed before use of these drugs in someone with impaired kidney function.
Other treatment may include corticosteroids and pain medicine especially if there is post herpetic neuralgia (pain along the nerves that can persist for weeks or months after the rash is healed). Depending on the specific complication in the eye, treatment may include antibiotic and/or corticosteroid eye drops and glaucoma treatment.
Preventing Herpes Zoster by Vaccine
Zostavax is a vaccine made by Merck & Co to prevent herpes zoster. Zostavax does not prevent the initial infection by the varicella zoster virus and does not cure the outbreak of herpes zoster once it has already occurred. However it can enhance one’s immune system to help prevent the dormant virus in the body from becoming reactivated. In clinical studies Zostavax reduced the shingles outbreak by approximately 50% and the pain and discomfort by 66%.
Like any medicine, the vaccine could possibly have some side effects, such as severe allergic reactions. Side effects of Zostavax are redness, soreness, swelling, or itching at the site of the injection (about 1 person in 3) and headache (about 1 person in 70).