Chickenpox Redux
Like other members of the herpes family (such as the herpes simplex viruses that cause cold sores and genital herpes), the varicella-zoster virus that causes chickenpox never completely leaves the body. Most people don't get chickenpox a second time. However, anyone who has had chickenpox has the potential to develop shingles, because after recovery from chickenpox, the virus settles in the nerve roots.Researchers are not sure exactly what triggers the virus to spontaneously start reproducing in nerve cells later in life and reappear as shingles. However, they do know the virus may reactivate when the immune system is weak.
Certain factors can cause the immune system to let down its guard. Age is one of them. Immunity declines with aging, so susceptibility to disease increases. The incidence of shingles and of resulting PHN rises with increasing age. More than 50 percent of cases occur in people over 60. Older people may also lack exposure to children with chickenpox, thereby losing an opportunity to boost immunity and prevent virus reactivation. Although most people have only one attack of shingles, about 4 percent will have further attacks.
People who have had chickenpox cannot "catch" shingles from someone who has it. However, people who've never had chickenpox can be infected with chickenpox if exposed to someone with an active case of shingles. The rash sheds the varicella-zoster virus and can be contagious. A caregiver or other person who lacks immunity developed from a prior case of chickenpox or the vaccine must avoid coming into contact with the rash or contaminated materials.
Also at risk for shingles are people with leukemia, lymphoma, or Hodgkin's disease, and those whose immune systems have been weakened because they are HIV-positive, or have undergone chemotherapy, radiation, transplant surgery with immunosuppression, or treatment with corticosteroids. Moreover, about 5 percent of people with shingles are found to have an underlying cancer, about twice the number of people in the population expected to have undiagnosed cancer.
It pays to be vigilant when unexplained symptoms occur. "New development of a rash or pain, especially when it occurs on only one side of the chest or face, should prompt a visit to the health-care provider," says Therese A. Cvetkovich, M.D., a medical officer in the Food and Drug Administration's Center for Drug Evaluation and Research (CDER).
Controlling the Outbreak
Although viral diseases can't be cured, doctors can prescribe oral antiviral medications, such as Zovirax (acyclovir), Famvir (famciclovir) and Valtrex (valacyclovir), that help control the infection by hindering reproduction of the virus in the nerve cells. "Antiviral therapy may shorten the course of an episode of shingles," says Cvetkovich. "However, therapy must be started as early as possible after symptoms develop, within 48 hours, in order to have an effect."To relieve pain, the doctor may recommend over-the-counter analgesics (pain-relieving drugs), such as ibuprofen and naproxen, or prescription drugs, such as indomethacin, all members of a class of medications known as nonsteroidal anti-inflammatory drugs. Acetaminophen is also commonly used to relieve the pain. If pain is severe, doctors may add stronger analgesics, such as codeine or oxycodone.
