By John Messmer
Penn State Family and Community Medicine
Penn State Milton S. Hershey Medical Center
Penn State College of Medicine
Just about every adult has had chickenpox -- called "varicella" in medical terminology, from the Latin for "little pox." Although chickenpox can be serious, for most of us, it was a fairly mild disease -- low fever and a rash consisting of blisters that rupture and scab accompanied by itching. Because chickenpox is so contagious, it spreads rapidly among children who have not yet had it. One episode confers lifelong immunity, so most people forget about it once they have recovered.
Unfortunately, the virus does not always go away. Anyone who has had chickenpox could be revisited by the virus in the form of shingles. If it comes back, it is not the mild to moderate, short-lived problem of childhood. Instead, it can become a source of chronic pain.
The name "shingles" comes from the Latin word "cingulum," or "belt," because shingles develops in a narrow band on one side of the body. The medical term is "herpes zoster," as it is caused by the herpes virus named the "varicella-zoster virus." "Zoster" is Greek for "girdle."
Most people have tingling, irritation or pain in one area for several days prior to the appearance of the rash. It can occur on any part of the body, but the chest and face are the most common. Many times it feels like a pulled muscle. After a few days, red bumps appear in small clusters in the area of pain. People who have been applying heat, thinking it was a muscular problem, often think they have a burn. As more bumps develop, they become clear blisters. Eventually the blisters open and develop scabs. The rash is usually very painful at this point and may be accompanied by malaise and fever. If it is on the upper face, it can enter the eye and damage the surface of the eye or the cornea, which can lead to blindness.
One in five adults eventually gets shingles. Most are over 50, although some children will develop it. About one million cases per year exist in the United States. Reduced immune system strength seems to be a major factor in getting shingles. Our immune systems grow weaker with age, diseases like HIV and certain kinds of treatment, such as immune suppressing drugs. When we recovered from chickenpox typically decades earlier, the virus did not die but became dormant in nerve cells near our spines. It cannot be killed or eliminated; it is undetectable as it hides, probably inside our DNA. Various types of stress seem to reactivate the virus. Unless our immune system is strong enough and remembers how to attack it, the virus travels down the nerve from our spine to erupt on the skin at the site where the nerve fibers sense pain.
As if it were not bad enough to have shingles, once the shingles clears up, the pain remains. For most people the pain goes away in four to six weeks, but for some it lasts years or decades. This chronic pain, termed "post-herpetic neuralgia" (PHN), can have a major impact on its victims. It can be severe, requiring potent suppressant drugs and narcotics to reduce the pain.
Most doctors think the risk of PHN can be reduced by treating the shingles outbreak as soon as possible with one of several antiviral medications: Famvir, Valtrex or Zovirax. While treatment can shorten the outbreak, some people may still get PHN.
About 10 years ago, a vaccine against chickenpox became available and has become standard in our arsenal of childhood vaccinations. It is also effective for older children and adults who have never had chickenpox, but requires two doses for people over 12. Reducing the occurrence of chickenpox in childhood may prevent shingles and PHN later in life. This possibility is not yet confirmed since the vaccine has been available for only 10 years.
Based on the chickenpox vaccine, a vaccine against shingles is being tested in an effort to boost immunity to the varicella-zoster virus. If our immune system is strong enough to fight the virus, it might prevent shingles. Initial study of the vaccine has shown that the risk of shingles was reduced by one-half.
For now, early treatment of shingles is recommended. If a painful rash develops in a localized area, contact a doctor -- the sooner the better. If it is on the face, it is imperative that antiviral medication be started and the eyes be examined for infection. Shingles is not contagious to anyone who has had chickenpox, but the virus is present in the blister fluid and can cause chickenpox in those who have not had it. Chickenpox can be devastating in people with compromised immune systems, so they should avoid anyone with active shingles. Pregnant women also should avoid anyone with active shingles in case they are not completely immune.
In the future, the chickenpox vaccine and the future zoster vaccine may make shingles and PHN a memory like measles, mumps and polio. For more information on shingles, go to http://www.nlm.nih.gov/medlineplus/shingles.html online.