ALLEVIATING THE PAIN OF SHINGLES

Chickenpox is generally an affliction of childhood, but the virus responsible for the infection can plague some people for the rest of their lives. When it strikes later in life, the result is a painful condition called shingles.

After a bout with chickenpox, the virus isn't removed from the body. Instead, it retreats to the nerves surrounding the spinal cord, where it can remain dormant for many years. A healthy immune system helps to keep the virus in check, preventing it from attacking a second time. With the advance of age or illness,however, the immune system can become less effective.

With the body's defenses weakened, the chickenpox virus can return. As it moves away from the spinal cord along nerve fibres, it leaves a trail of blisters on the overlying skin. The distinctive shingles rash can appear virtually anywhere on the
body, but it frequently arises on a single side of the torso, face, or legs. While the skin eruption can be unsightly, the pain associated with shingles can be excruciating.

In most cases, the rash and the accompanying pain will disappear in three to four weeks, but in some cases, the pain can linger for weeks, months, or even years. This condition, called post-herpetic neuralgia, affects 40 percent of shingles sufferers over the age of 60. The pain, often described as a stabbing, burning, or shock-like sensation, can be debilitating. In some cases, the skin is so sensitive that even the lightest touch can be very painful.

Although the exact cause is unknown, experts speculate that it is likely the result of nerve damage caused by the virus. After a case of shingles, the affected nerves may become more excitable, firing off pain signals more easily and more frequently. In some individuals with post-herpetic neuralgia, the pain is so severe that it interferes with their normal daily life. More than 60 percent of patients with the condition
experience difficulty sleeping, and half say that their enjoyment of life is significantly diminished.

In May 2006, the U.S. Food and Drug Administration approved the first vaccine to prevent shingles for adults aged 60 and over. Clinical trials showed that use of the vaccine reduced the risk of developing shingles by half, and decreased the likelihood of developing post-herpetic neuralgia by two-thirds.

While the vaccine may help prevent shingles and post-herpetic neuralgia, it isn't considered to be a treatment for either condition. Patients with active cases of shingles shouldn't be vaccinated until their symptoms have resolved. In the meantime, prescription antiviral medications can help reduce the severity of shingles, as well as the likelihood of developing post-herpetic neuralgia. Although these drugs were previously believed to work best when started within 72 hours of developing symptoms, newevidence has shown that they can be beneficial even when taken later in the course of the illness.

In addition to antiviral drugs, prescription pain medications are an important part of the medical management of shingles. Recent research suggests that aggressive pain control, started early in the treatmentperiod, can reduce the likelihood that patients will develop post-herpetic neuralgia.

In the past, many patients turned to over-the-counter remedies or prescription drugs for relief, with varying results. In 2004, a new drug called Lyrica received FDA approval for the treatment of post-herpetic neuralgia. In clinical studies of patients with post-herpetic neuralgia, individuals taking the drug experienced significant reductions in pain as early as a week after beginning treatment. Over a period of several weeks, up to half of patients taking the highest approved dose reported at least a 50 percent reduction in pain.