homehome Home chatchat Notifications


Woman's nut allergy triggered after sex in bizarre first

She was allergic to Brazil nuts, but it wasn’t any she ate that sent her to the hospital.

Tibi Puiu
January 10, 2025 @ 7:48 pm

share Share

AI illustration of legumes
Illustration by Midjourney.

When a 20-year-old woman in the United Kingdom rushed to the hospital with a swollen face, hives spreading across her body, and difficulty breathing, doctors knew immediately what likely happened. The symptoms seemed familiar — an allergic reaction — but the trigger was anything but ordinary.

Indeed, the woman has a severe allergy to Brazil nuts and experienced reactions in the past after ingesting them. But this time, she hadn’t eaten any nuts. Instead, she had engaged in unprotected vaginal sex with her habitual partner shortly before her symptoms began.

What made the case truly perplexing was the thorough preparation her partner had undertaken. Hours before their intimacy, he had eaten Brazil nuts. But since then, he had bathed, brushed his teeth, and cleaned under his fingernails. Despite these precautions, her body reacted as if it had been directly exposed to the allergen.

A bizarre case

The doctors delved deeper. Through a series of skin prick tests using the man’s semen, they uncovered the cause. When the sample contained traces of Brazil nut allergens, it triggered a welt on her skin, confirming their hypothesis: the allergenic proteins had been transmitted through his semen during intercourse.

“Skin prick testing with the boyfriend’s semen after Brazil nut consumption confirmed significant reactivity whereas a sample before nut consumption was negative. We believe this to be the first case of a sexually transmitted allergic reaction,” wrote doctors from St. Helier Hospital in a 2007 case report.

The peculiar case highlights how sensitive food allergies can be, even when the allergen isn’t consumed directly. Although similar cases involving intimate contact have been documented, such as reactions caused by kissing, the transmission pathway in this instance was unprecedented.

For the young woman, the outcome was fortunately manageable. After taking an oral antihistamine, her symptoms subsided within 45 minutes, Live Science reported. The next day, she felt fatigued but otherwise fine. Still, the incident prompted doctors to recommend carrying antihistamines and an adrenaline pen at all times. Abstaining from sexual contact following nut consumption by her partner was deemed vital.

While the young woman’s story ends on a positive note, it serves as a call for heightened awareness regarding allergies: sometimes, even love can carry unexpected dangers.

share Share

Dolphins and Whales Can Be Friends and Sometimes Hang Out Together

They have a club and you're not invited.

Cats in a Finnish Village Have a Coat Pattern That's Never Been Seen Before

These beautiful and unique cats have similarly unique DNA.

Scientists Uncover 505-Million-Year-Old Penis Worm with a Mouthful of Bizarre Teeth

Evolution was trying things out.

The Bishop, the Cleric, and the Woman on Seashells: Scientists Recreate the Faces of Scotland’s Early Christians

Their faces were lost to the world. Now, science has brought them back.

Scientists May Have Found a New Mineral on Mars. It Hints The Red Planet Stayed Warm Longer

Scientists trace an enigmatic infrared band to heated, oxygen-altered sulfates.

Why Some Pro Athletes Keep Getting Better as They Age, Even In Their Late 30s

The same principles that help athletes on the court, field or track can help you regulate stress and adapt to changes in everyday life.

These Seabirds Poop 5% of Their Body Weight Every Hour and They Only Do It While Flying Over the Ocean

Scientists strapped cameras to shearwaters and discovered nonstop midair pooping.

Beef is Driving Huge Deforestation and Emissions, But Is Regenerative Grazing a Solution?

Beef production contributes to numerous global crises, from climate change to habitat destruction to biodiversity loss.

It Costs Less Than A Hundredth Of A Cent To Stop An Hour Of Chicken Pain, Scientists Say

Researchers attempt to measure animal pain in dollars and hours.

A Croatian Freediver Held His Breath for 29 Minutes and Set a World Record

Croatian freediver Vitomir Maričić smashed a world record and pushed human limits underwater.