Shingles (herpes zoster) is a disabling disease of sensory nerves and skin caused by the reactivation of a virus, varicella zoster virus (VZV). VZV infects persons during childhood or adolescence and causes chickenpox (varicella). VZV is fascinating because it is not cleared from the body after the chickenpox resolves. Instead, it has the ability to establish a dormant infection of sensory nerves for the lifetime of the host and retains the capacity, after many decades, to emerge at unpredictable times to cause shingles.
Although shingles can occur in anyone who has been infected with VZV, it is much more common in older adults and in persons who have diseases that impair the immune system such as leukemia, Hodgkin’s disease, and HIV infection. Shingles is more likely to occur in older persons because of a decline in immunity to VZV with aging. The incidence of shingles increases sharply at around 50 to 60 years of age. The incidence in persons over 65 years of age is as high as 11 per 1,000 persons per year.
The first symptom of shingles is usually a prodrome of pain or discomfort in a localized area. This worrisome prologue bewilders patients, caregivers, and physicians, and it masquerades as many other painful conditions in the elderly. Eventually, the virus infects cells in the skin and produces a characteristic rash. The rash is on one side of the body and in the area of skin innervated by the sensory nerve bundle in which VZV is reactivating (called a dermatome). It begins as a red bumpy eruption and then usually develops blisters. Along with the rash, most patients experience pain in the involved area. The characteristic rash and pain make shingles easy to diagnose.
The rash heals in 2 to 4 weeks, but the pain continues after the rash has healed in as many as 60% to 70% of persons over 60 years of age and develops into a chronic pain condition known as postherpetic neuralgia. Postherpetic neuralgia is much more common in older adults than in younger adults and can have a devastating impact on elders’ quality of life. Some patients suffer from severe pain after the lightest touch of the affected skin by things as trivial as a cold wind or a piece of clothing.
The main goal of the treatment of shingles in older adults is the reduction of pain. Antiviral therapy with a drug such as acyclovir, famciclovir, or valacyclovir can reduce the acute pain and the duration of postherpetic neuralgia, especially if given early in the shingles episode. Corticosteroid drugs such as prednisone do not affect postherpetic neuralgia. Pain control with analgesics is also important during shingles. Sometimes, anesthetic nerve blocks reduce severe pain in persons not responding to antiviral and analgesic drugs. Once postherpetic neuralgia is established, it can be very difficult to treat. However, drugs such as gabapentin, pregabalin, opioids, and tricyclic antidepressants, as well as a 5% lidocaine patch, may reduce postherpetic neuralgia pain in some older adults.
The incidence of chickenpox has declined dramatically in the United States recently because of the widespread use of the varicella (chickenpox) vaccine in children. The vaccine is very effective in preventing chickenpox. As the cohorts of children now receiving the vaccine age into older adulthood, it is likely that shingles and postherpetic neuralgia will also decline markedly. However, there are still billions of people who harbor VZV and are at risk for shingles. Recently, investigators reported that a zoster (shingles) vaccine reduced the incidence of shingles by 51% and the incidence of postherpetic neuralgia by 66% in adults over 60 years of age. Experts are hopeful that both shingles and chickenpox can be reduced markedly with the widespread use of the two vaccines.
Pain; Skin Changes
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