Shingles (herpes zoster ophthalmicus)
What are shingles?
Shingles is a painful condition affecting the skin and nerves. It is caused by the herpes zoster virus, also known as varicella; the same virus that causes chickenpox in children. If this virus infects the skin around an eye or the eye itself, it is termed herpes zoster ophthalmicus, also known as HZO.
How do I know if I have HZO?
If you have a rash with small blisters and lesions on your forehead, on the side of your face or around your eye, you may have HZO. When zoster blisters appear at the tip of the nose, the likelihood of HZO is significantly higher. In addition to pain, influenza symptoms usually precede a zoster rash by a few days or a week: fatigue, malaise, low-grade fever. Numbness and tingling may also precede the zoster rash in the area of future blister eruption.
Is this herpes virus the same one that causes cold sores?
No. Facial and genital herpes are termed herpes simplex viruses. When this virus affects the eye, it is termed ocular herpes simplex. It can cause damage to the cornea, resulting in corneal and vision loss.
Herpes zoster is a different virus. It is the virus responsible for chickenpox and shingles. Sometimes, however, herpes simplex viral infections can closely resemble herpes zoster. An experienced ophthalmologist will be able to distinguish between the two viruses, initiating treatment to hasten recovery regardless of which herpes virus a patient has acquired.
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How does one acquire HZO?
People who develop HZO usually had chickenpox or, at minimum, have been exposed to a herpes zoster virus. Following the infection, virus particles remain in the body’s nerve cells where they lay dormant for years. Sometime later, possibly decades, the virus is reactivated causing inflammation of the skin and nerves. This condition is termed shingles. Shingles can appear on any part of the body. When this viral condition appears in or near the eye, it becomes herpes zoster ophthalmicus.
Why is it painful?
As the reactivated virus grows and travels along the nerves, it inflames the nerve fibers that carry sensations of pain. The farther and wider the virus travels, the more nerve fibers are affected. When the virus reaches the skin, the inflammation results in blisters and skin necrosis. In HZO, inflammation may damage delicate eye tissue as well as surrounding structures. If untreated, this damage may lead to vision loss. That is why any abnormal or painful condition around the eye should be examined by an ophthalmologist as soon as possible. The sooner the disease is diagnosed, treatment can begin and the sooner recovery occurs.
What causes the virus to reactivate?
More than 90% of adults have either had chickenpox or been exposed to the varicella-zoster virus. Medical researchers believe as a body ages, the potency of its immune system declines. At a certain age, the immune system is unable to suppress virus reactivation. Medical experts are unable to predict when a varicella-zoster virus will reactivate or, among patients who have a reactivated virus, where the herpes zoster virus will present itself on the body.
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How prevalent is herpes zoster?
In America, the reported annual incidence of herpes zoster varies from 150 – 340 cases for every 100,000 people. For people over the age of 75, the incidence increases to 1,000 per 100,000 or 1% of this population.
How prevalent is herpes zoster ophthalmicus?
10 – 25% of all herpes zoster cases are ophthalmicus.
How is HZO treated?
Antiviral medications such as Valtrex, Famvir (famciclovir) and acyclovir represent the initial treatment. Eye drops, topicals or tablets containing steroids may be prescribed to reduce inflammation. Inflamed tissue around the eye may impair the ability to blink so eye lubricant is applied. If the patient is experiencing pain, analgesic medications may be prescribed. HZO may cause secondary infections in tissues in and around the eye. These infections are usually treated with antibiotics.
What complications can occur from HZO?
Corneal damage is the most common complication of HZO, ranging from mild irritation and blurry vision to permanent swelling and scarring of the cornea.
Iritis or inflammation inside the eye can cause pain, secondary glaucoma and photophobia which can result in cataracts. Retinal damage is possible although rare.
Eye muscle paralysis can develop as a result of zoster inflammation in the nerves and muscles. This complication causes the person to experience double vision.
Skin related complications include a rash on the forehead progressing to blisters and possible necrosis - tissue death – causing scarring on the forehead.
Essentially, all ocular structures, tissues, nerves and fragile blood vessels are susceptible to the dangerous inflammation caused by the herpes zoster virus. Fortunately, prompt evaluation and treatment by an experienced ophthalmologist can prevent most of these serious ocular complications.
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How long does HZO last?
Patients recover from uncomplicated HZO in a few weeks. If complications occur, recovery takes more time. The age of a patient affects recovery time as does the patient’s health. Patients with HIV, AIDS or cancer experience extended, complicated recoveries.
Chronic pain from nerve damage caused by the herpes-zoster virus (post herpetic neuralgia) can affect about 20% of patients with shingles. This pain tends to be more severe among the elderly.
Are people with HZO contagious?
Patients with herpes zoster can transmit the varicella-zoster virus. People who have not had chickenpox must avoid patients with HZO – especially unvaccinated children and pregnant women.
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