ABC News April 9, 2018

One of the world’s hottest peppers offers insights into headaches

WATCH: Hot off the press: Can peppers cause headaches?

A man rushed to the hospital with an excruciating headache after participating in a chili-pepper-eating contest may have triggered a hot medical discovery.

Doctors who assessed him wondered what could have caused the massive pain in his head. After excluding a life-threatening bleed and a tear of the arteries in his neck, they were left with a more bizarre explanation: the chili peppers.

The man had taken part the pepper-eating contest earlier in the day, during which he had eaten a "Carolina Reaper," one of the hottest varieties of peppers on Earth.

After scanning his head, doctors found that several of his brain’s arteries had narrowed. They diagnosed him with "reversible cerebral vasoconstriction syndrome," a rare side effect associated with some medications.

Fortunately, the patient improved. A second scan five weeks after showed his brain's arteries had returned to normal.

However the condition isn’t always harmless, it has previously been linked to stroke. The man's symptoms included a severe "thunderclap headache," dry heaves and neck pain, but a thunderclap headache can also occur by itself.

So should people avoid spicy foods?

"We would not advise against eating hot peppers at this time, but we would recommend the public be cautious about these adverse effects. Seek medical attention immediately if [you] develop sudden headaches after eating hot peppers," Dr. Kulothungan Gunasekaran from the Henry Ford Hospital in Detroit that was behind the report told ABC News.

Since cerebral vasoconstriction syndrome has previously occurred without an identifiable cause, doctors can’t be sure eating peppers was to blame. But they do think it's plausible that it caused the man's symptoms in this case.

Though it may have spiced up the doctors' day, it's something they're unlikely to see again. The report, published in BMJ Case Reports, is the first that links hot peppers to reversible cerebral vasoconstriction syndrome.

Gunasekaran was unable to comment on exactly how common this effect might be.

"Unfortunately we don’t have any data as there is no randomized control trial in this field," he said.

There have been other reports about the possible harmful effects of spices. In 2012, doctors in Turkey reported that a patient had suffered a heart attack after taking an excessive number of cayenne pepper pills for slimming. Another study found that capsaicin -– the active ingredient in peppers -– could increase heart rate and blood pressure.

These findings led doctors to suggest that capsaicin might be "vasoactive," meaning it affects how blood vessels function. That could be how the pepper may have caused this man's headache, by constricting the vessels in his head.

Conversely, some patients are prescribed capsaicin for pain associated with conditions like arthritis, diabetic neuropathy and muscle aches.

A study published in the Journal of Clinical Pharmacy and Therapeutics even found that it was effective in treating headaches -- although that might not work for the man at the pepper-eating contest.