Stroke Risk Spikes After Shingles Episode: Study
But getting antiviral meds to treat painful rash lowers chances of brain attack, researchers add
By Dennis Thompson
THURSDAY, April 3, 2014 (HealthDay News) -- People with shingles face a significantly increased risk of stroke in the weeks following the first signs of the painful skin rash, new research suggests.
Patients' overall stroke risk is highest in the first month after the onset of shingles, when they are 63 percent more likely to have a stroke, said study author Dr. Sinead Langan, a senior lecturer at the London School of Hygiene and Tropical Medicine. The risk tapers off during the following five months, she added.
Shingles patients also have a threefold increased risk of stroke if they develop the rash around one or both eyes, according to the report published online April 3 in the journal Clinical Infectious Diseases.
However, the study also delivered some good news for people with shingles, Langan added.
"We found that the risk of stroke was lower in people who were treated with antiviral medications for their shingles, compared with those not treated with antivirals," she said. "That hasn't been shown before, that treating with antivirals might make a difference."
The study didn't prove that shingles causes a stroke; it only found an association between the viral infection and stroke risk.
The apparent role of shingles in stroke is a little-known phenomenon that will emerge as a major health issue in coming years, said Dr. Maria Nagel, an assistant professor of neurology at the University of Colorado School of Medicine.
Shingles (herpes zoster) is caused by the same virus that produces chicken pox. The virus lies dormant in people's bodies for decades, and when they are older it reactivates and produces shingles.
"More than 95 percent of the world population is infected with this virus, and by the age of 85 about 50 percent of the population would have reactivated the virus and gotten a rash," said Nagel, who co-wrote an editorial that accompanied Langan's study.
An estimated 1 million adults in the United States suffer from shingles every year, according to background information in the study.
There are a couple of ways that the shingles virus may raise the risk of a stroke, Langan and Nagel explained.
The virus can invade the walls of blood vessels, infecting the cells and increasing the chance that a vessel could clog or rupture, Nagel said.
That's likely the reason why stroke risk is so pronounced in people with shingles around their eyes -- from that location, the reactivated virus has a direct pathway into the arteries of the brain, she said.
Shingles also promotes inflammation in the body, which can cause arterial plaques to rupture and induce a stroke.
The new study involved 6,584 stroke victims who also suffered from shingles, drawing from a database of information of patients in over 600 general practices in the United Kingdom.