Shingles, or herpes zoster, is a painful condition caused by reactivation of latent varicella-zoster virus, the same virus which causes chickenpox. After an episode of chicken pox, this virus travels into sensory nerve roots and becomes dormant. Many years later, for reasons that are not well understood, the virus “wakes up” and travels into the skin causing pain, which can be severe, as well as a blistering rash. The rash typically occurs in a specific pattern along a ‘dermatome,’ a band-like area of skin on one side of the body to which a single sensory nerve segment travels, usually along the chest or abdomen. Less frequently, the face or scalp is involved.
It is estimated that the lifetime risk of developing shingles is about 30%, with approximately one million cases diagnosed annually in the United States. While most people will only experience one episode of shingles, second or third episodes are possible.
The disease usually begins with pain, burning, tingling, or itching within the affected area. Headache, fatigue, and light sensitivity may also be present. Approximately three to five days later a rash develops, with redness of the skin and clustered small blisters, or vesicles. New vesicles continue to form over the next three to five days, followed by crusting of the lesions with ultimate healing over two to four weeks. Sometimes healing leads to scarring or change in pigmentation of the skin.
Approximately 20% of shingles cases involve the trigeminal nerve of the face, and many of those will affect the eye. Known as herpes zoster ophthalmicus (HZO), this eye involvement can cause serious complications. Mild redness of the eyelids or conjunctiva (surface membrane of the eye) may be the first sign of trouble. Some go on to develop keratitis, an inflammation of the cornea, or uveitis, inflammation within the eye itself. Both of these conditions are serious and can lead to scarring, chronic pain, and loss of vision. Early diagnosis and initiation of therapy is vital to a good outcome.
Many patients suffering an outbreak of shingles will develop post-herpetic neuralgia, or PHN, a chronic pain syndrome which can be severe and debilitating, often lasting months to years. Some studies have found the incidence of PHN to be as high as 70%, though the exact symptoms used to define the condition have varied from study to study, making the exact incidence difficult to determine. Clearly, however, the frequency, duration, and severity of PHN increases with increasing age, probably affecting more than 50% of those over 60 years of age following an outbreak of shingles.
Occasionally, shingles lesions can become infected with bacteria, typically Staphylococcus aureus, requiring topical or systemic antibiotics. Nerve palsies (muscle weakness due to nerve injury) sometimes occur. More severe complications tend to affect immunocompromised individuals, who may experience meningitis, encephalitis (brain inflammation), pneumonitis (lung inflammation), or hepatitis (liver inflammation).
The varicella-zoster virus can be transmitted from someone with active shingles to another individual who has not yet had chickenpox or the chickenpox vaccine. Transmission is only possible when the rash is blistering- once the lesions have crusted a person is no longer contagious. Transmission is via direct contact or exposure to airborne virus, and covering the lesions can reduce the risk. A susceptible individual would develop chickenpox, not shingles, if exposed.
A number of antiviral medications exist of the treatment of zoster. Acyclovir (Zovirax®), famciclovir (Famvir®), and valacyclovir (Valtrex®) have all been FDA-approved for this purpose. Treatment shortens the duration and overall severity of the illness but will not prevent post-herpetic neuralgia. Medication is most effective when instituted early in the course of the disease, preferably within the first 24 to 48 hours.
Some studies have shown that treatment with oral corticosteroids, such as prednisone, may reduce the incidence of post-herpetic neuralgia, particularly in those over 60 years of age.
Post-herpetic neuralgia can be difficult to treat, with variable response to multiple pain and neurologic medications. Multiple medications might be tried, with treatment individualized as necessary.
vaccine for shingles, known as ZOSTAVAX®, has been FDA-approved and available from Merck since 2006. Studies demonstrated that the vaccine is effective in reducing the incidence of shingles by 50%, and the incidence of post-herpetic neuralgia by 66%. Based on these findings, the Centers for Disease Control and Prevention recommended in May, 2008 that all adults over 60 years of age receive a single dose of this vaccine, unless a contraindication exists. Contraindications generally pertain to immunocompromised individuals.
The vaccine is recommended even for those who report a prior episode of shingles, as there is no evidence that an episode of shingles protects against further episodes.
We strongly recommend that all our patients over 60 years of age discuss this with their primary care physicians (PCP) and, if not contraindicated, obtain the zoster vaccine.