Eye Shingles May Increase Stroke Risk

By Robert Shmerling, M.D.
Content provided by the Faculty of the Harvard Medical School

People who have had shingles in the eyes may have a greater risk of stroke in the next year, a new study suggests. Researchers looked at insurance records for 658 adults who had shingles in their eyes. This is also called ophthalmic or ocular shingles. It causes pain, itching and blisters around or in the eye. Researchers compared these people to others the same age and sex who did not have shingles. About 8% of the group who had shingles of the eye had a stroke in the next year. Only 2% of the shingles-free group had strokes in that year. Researchers then adjusted the numbers for differences between the two groups — such as high blood pressure — that could affect stroke risk. People who had ocular shingles still showed the same higher risk. The study appeared in the journal Neurology. Reuters Health news service wrote about it March 3.

What Is the Doctor's Reaction?

You may think of chickenpox as a mild condition or as a rite of passage for kids. The itchy rash may keep your kids out of school, but it's usually harmless.

But if you've ever had shingles, you may think of chickenpox differently.

Shingles is a painful condition that can be serious. It's caused by the varicella-zoster virus, the same one that causes chickenpox. After a person recovers from chickenpox, the virus lies dormant in the body. This means that it's still around but not causing illness. Many years later — often decades later — the virus can become active again. This time it causes shingles, a painful, burning rash over a patch of skin. Anyone who has had chickenpox can develop shingles.

The pain can sap your strength and energy. And it can last long after the rash goes away. This condition is called post-herpetic neuralgia. If that's not bad enough, up to 20% of shingles outbreaks involve the eye. This is called ocular shingles. It can cause vision loss. You can take medicines for shingles, but they tend not to reduce symptoms much.

A new study brings even more bad news about shingles. Researchers have discovered a link between ocular shingles and stroke. The study is in the new issue of the medical journal Neurology. Researchers looked at medical records for one year for 658 people who had recovered from ocular shingles and 1,974 people who didn't have shingles. They compared stroke rates in the two groups.

  • The stroke rate was more than four times higher among those with ocular shingles.

  • The stroke rate was 8.1% among those with ocular shingles. It was just 1.7% among those without the condition.

  • People with ocular shingles had a higher stroke risk even after researchers accounted for known stroke risks, such as high blood pressure and diabetes. However, information about another important risk factor — smoking — was not available.

The results were the same even if people with ocular shingles received antiviral drugs.

It's not clear from this research how ocular shingles might increase stroke risk. And it's not clear if the effect is direct. For example, shingles involving the eye could somehow interrupt blood flow to the brain, causing stroke. If that's true, the findings of this study could provide a new reason to be vaccinated for shingles: stroke prevention.

Since 2006, a vaccine has been available to prevent shingles. Experts estimate that 250,000 people could be spared from shingles if the vaccination were routine. A similar number of people could still develop shingles, but with less severe symptoms. Yet the vaccine is underused. At least part of the reason is that the shot costs up to $300. Many health insurance plans do not cover its cost.

On the other hand, the link between ocular shingles and stroke might be indirect. For instance, maybe people who develop ocular shingles are sicker in other ways that make them more prone to stroke.

What Changes Can I Make Now?

You can't get shingles if you don't get chickenpox. In 1995, the FDA approved a vaccine to prevent chickenpox. It's recommended for:

Your Guide to Shingles