The surprising reason you’re safer from allergic reactions in-flight than on the ground

They’ve cracked the case.

In new research, UK allergy and aviation medicine specialists dispel the widely held belief that nut allergens spread through airplane ventilation systems.

“In fact, food-induced allergic reactions are around 10–100 times less common during flights than ‘on the ground,’” the researchers wrote in their scientific review published Tuesday in the journal Archives of Disease in Childhood.

In examining studies of airborne food allergens, the authors say that allergen residues on surfaces inside the cabin pose the greatest in-flight risk — a risk likely exacerbated by fast airline turnaround times.

Cleaning tray tables, seat surfaces and seatback entertainment systems at the start of a flight with sanitizing wipes “is particularly important,” the study authors wrote, “given the minimal cabin cleaning which occurs in between flights, especially with low-cost carriers.”

The researchers say that announcements asking passengers not to consume nuts during a flight are unlikely to reduce the risk of in-flight allergic reactions — and instead might provide false reassurance.

Air is exchanged every three to four minutes during large commercial flights — about half is recirculated air that has passed through filters that remove dust, vapors and microbes and capture airborne food particles. The other half is outdoor air.

Ventilation systems are designed to circulate air across the aircraft, rather than along the passenger cabin, the study authors explained, reducing the potential for spreading flier-generated contaminants through the cabin.

Allergic reactions to airborne food particles are rare. Exceptions include people sensitive to seafood exposed to vapors from fish or shellfish and bakers who develop asthma from inhaling wheat flour as part of their job.

In 2019, reality star and entrepreneur Bethenny Frankel, who has a rare fish allergy, called a flight that she took where bass was served a “death trap.”

As for peanut allergens, they “can be detected at very low levels in the air when shelling nuts, but the dust settles quickly and can only be detected in very close proximity to the nuts,” the study authors wrote.

About 4.6 million US adults have a peanut allergy, with over 800,000 of them developing the allergy as adults, according to 2021 research.

An allergic reaction can lead to hives, a swollen throat and lips, breathing difficulties, stomach cramps, nausea, vomiting, dizziness, and, in severe cases, anaphylaxis, a life-threatening reaction requiring immediate medical attention.

Fliers at risk of anaphylaxis should carry an EpiPen in their carry-on luggage, the authors of the latest study advise, as these aren’t always included in onboard medical kits, nor are cabin crew always allowed to use them.

“Airlines should have clear policies relating to food allergies which are easily available from their websites or on request,” the researchers added. “These policies should be applied consistently by both ground staff and cabin crew, in order to provide reassurance to food-allergic passengers and their caregivers.”