At Risk for Shingles and Postherpetic Neuralgia?
Experts explain the causes and treatments of shingles pain.
Shingles Symptoms: What Should You Look For?
Unlike the whole-body rash of chickenpox, the shingles rash is limited to the area of skin assigned to the infected nerve. The rash usually consists of small bumps that may turn into blisters before bursting and crusting over. If shingles appears on the face, the eye can be affected, posing a threat to sight.
Also unlike chickenpox, this rash hurts, sometimes intensely. People typically describe shingles pain as burning, stabbing, or electrical.
"Shingles can be almost unbearably painful," says Jeffrey Ralph, MD, assistant professor of neurology at the University of California in San Francisco and a fellow of the Neuropathy Association. "The nerve itself is inflamed. The pain can sometimes come even weeks before a rash appears."
When Shingles Becomes Painful Postherpetic Neuralgia
In 10% to 20% of these people, however, the pain of shingles keeps hanging on after the rash is gone. "These folks go on to get postherpetic neuralgia, and we're not exactly sure why," Ralph tells WebMD. "Either the pain of shingles never leaves, or it resolves, comes back, and never goes away completely."
PHN typically occurs in the area where the shingles occurred. The pain can be intermittent or constant, and it can take on any of the diverse qualities of shingles pain. Normal touching of the skin can set it off, Ralph adds. This is called allodynia.
The pain of postherpetic neuralgia can interfere with daily activities, exercise, sleep, and sexual desire. Irritability and depression often follow. "Generally, it makes people feel terrible if it can't be controlled," Rumbaugh says.
Why the pain of postherpetic neuralgia persists has mystified researchers. It's not due to ongoing infection by VZV, but is thought to be due to residual damage or inflammation in the nerve after shingles resolves. It's also impossible to predict who'll get shingles or postherpetic neuralgia, although age, race, and health seem to have some impact.
Shingles and Postherpetic Neuralgia: What Are the Risk Factors?
You can't control whether you'll catch the chickenpox virus. Fully 99.5% of adults in the U.S. carry it, whether or not they remember having had chickenpox. But why do one-third of those people get shingles -- and some of them go on to develop postherpetic neuralgia?