If you thought chickenpox was a "once and done" childhood illness, you're only two-thirds right. For about one million American adults each year, that long-forgotten rash returns in a new painful form: shingles.
The pain of shingles can be excruciating, but the condition goes away in a few weeks -- for most people. In some unlucky folks, shingles pain doesn't end when the rash goes away. It goes on. And on. This is called postherpetic neuralgia (PHN), a form of neuropathic pain that can last for months or years, even after the virus is no longer active.
"Postherpetic neuralgia can make people feel truly miserable," says Jeffrey Rumbaugh, MD, PhD, assistant professor of neurology at Johns Hopkins University and a member of the American Academy of Neurology. "For some, it's something they live with once in a while. For others, it can be daily, severe pain that may last a lifetime."
Some people are at higher risk for shingles and postherpetic neuralgia than others. But when used correctly, available treatments can prevent postherpetic neuralgia or at least stop it from becoming a permanent, painful companion.
What Causes Shingles Pain?
Chickenpox, shingles, and postherpetic neuralgia all result from infection with a single virus called varicella zoster virus (VZV). Most people catch the varicella zoster virus as children, itch and shiver through the rash and fever of chickenpox, and get better.
But that's not necessarily the end of the story of varicella infection. After a bout of chickenpox, our immune systems never completely eradicate the VZV virus. They just chase it into hiding. Varicella retreats into nerve cells deep under the skin, near the spine.
For most of us, VZV lies dormant inside our bodies throughout our lives, never causing further problems. In about one-third of people, however, VZV infection has a second act. The virus emerges from hiding, travels along a nerve to the skin, and erupts in a bumpy, painful rash on one side of the body. This sneak attack is called herpes zoster, or shingles. (Varicella zoster virus belongs to the family of herpes viruses, but does not cause cold sores or genital herpes.)