Shingles

Hot Peppers Rescue Shingles Sufferers

Turns out that two pains can make a right. Hot peppers are a key to reducing the misery associated with shingles, or herpes zoster, a viral infection that frequently causes a painful rash, according to results from a promising new clinical trial.

The study found that a high dose of capsaicin, the chemical in hot peppers that makes eyes water and mouths sting, applied through a skin patch can be surprisingly effective in relieving postherpetic neuralgia, the debilitating nerve pain that is frequently a complication of shingles.

The study involved 402 patients at 55 research centers in the United States, including the University of Wisconsin School of Medicine and Public Health. Results were published in the December edition of The Lancet-Neurology. 

Shingles

Tests of the skin patch found that about 40 percent of sufferers experienced pain relief that lasted up to three months. "We were surprised at the long term pain relief,'' Dr. Miroslav Backonja, a professor of neurology at SMPH and the study's lead author, said in a press release. "People had pain relief for up to 12 weeks from a patch that was applied for an hour."

Shingles occur when the herpes zoster virus, which also causes childhood chickenpox, becomes active again after lurking dormant for years and even decades in the nerve roots. The virus can damage the nerves and cause blisters, often on the body and head. Pain can persist months and even years after the rash disappears.

Sufferers describe the pain as excruciating burning and itching. In one extreme case reported in a scientific journal, a patient scratched through her skull into her brain. One of UW neurologist Backonja's patients quit her job because the rash on her back was so sensitive she couldn't wear clothing.

Still, Backonja said he was concerned that no one would want to participate in the trial because of the strength of the capsaicin. Topical capsaicin cream, which is sold over the counter as a remedy for arthritis pain, contains concentrations of 0.025 percent to 0.075 percent. The eight percent concentration used in the trial is more than a hundred times stronger.

"My first concern was that nobody would be able to tolerate it. I was flabbergasted how well they did,'' Backonja said.

Patients had their skin numbed with a cream before the patch was applied. Some were also given oral pain medicine for the pain caused by treatment.

While shingles tend to disappear quickly in younger patients, Backonja said that more than 40 percent of people older than 65 years who have an outbreak of the blisters would develop the painful neuralgia that can follow. "This is a problem that plagues the elderly, and this is becoming a health care problem because that is the most rapidly growing segment of the population," he said.

Backonja said capsaicin may work by "pruning back" damaged endings of nerve cells. "What we think happens is that the virus damages the nerve endings, and these damaged nerve endings are like live wires,'' Backonja said. "If you 'prune them back', they stop short-circuiting."

Capsaicin is known to use the same pathways the nerves use to conduct the sense of heat, which is probably why spicy salsa makes you feel warm all over.

So could simply eating a lot of hot peppers ease symptoms, too? Maybe. Backonja said he once had a patient who treated his shingles by downing lots of hot salsa. But the patches, Backonja said, will be more effective. Plus they are a topical treatment, which means doctors don't have to worry about interactions with other drugs when prescribing them.

NeurogesX, a California company that is hoping for FDA approval of the shingles patch, financed the study. The company says it expects European Union approval in early 2009, and that the FDA will begin reviewing the drug for U.S. approval late in 2009.

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