People suffering from shingles are at a higher risk for stroke, say researchers from the University of Colorado Anschutz Medical Campus. The study authors found that the risk for stroke remains elevated for a year after the painful rash disappears.

According to Pharmacy Times, shingles, also called herpes zoster, is caused by the varicella-zoster virus ─ the same virus that causes chicken pox and then can reactivate later in life and trigger shingles. The risk of stroke in patients with shingles is especially higher in those under the age of 40, for whom the vaccine is not typically recommended.

Andrew Bubak, assistant research professor in the department of neurology at the University of Colorado School of Medicine, investigated the mechanism behind the increased stroke risk.

He found that exosomes ─ tiny sac-like structures formed inside cells that contain some of the cells’ DNA and RNA ─ travel through the blood to other parts of the body and can cause inflammation and thrombosis (blood clots that block veins or arteries) away from the site of actual infection.

“That could ultimately lead to a stroke in patients,” he said. Bubak and his team collected plasma samples from 13 patients with shingles and 10 without to extract exosomes from the plasma. The samples were gathered at the time of infection and at a three-month follow-up.

They discovered prothrombotic exosomes, which can lead to blood clots, in the plasma of the patients with shingles. And at the three-month follow-up they also found proinflammatory exosomes in the patients, which also carry a risk for stroke.

The findings suggest that in some people with shingles, the virus doesn’t return to its latent state or the exosomes that cause the prothrombic state survive therapy for the disease. Bubak suggested that using antiviral agents longer may help, along with the addition of antiplatelet and anti-inflammatory medications.

Bubak added that the research indicates that individuals who are at risk of having a stroke get vaccinated for shingles.

“If these findings are confirmed with a larger longitudinal study, this could change clinical practice,” he said in a news release , adding that most physicians are not aware of the connection between stroke and shingles.

“But it’s really important and so easily mitigated, “said Bubak. “Send them home with antiplatelet agents.”