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Travel With Allergies

Anaphylaxis in the Air: Two August Airline Incidents

Two food allergy emergencies occurred in August 2014 aboard two long-distance flights, reminding all of us in the allergy community of the importance of being prepared for anaphylaxis.

The first incident occurred when a 4-year-old Irish girl began to have a severe reaction during a United Airlines flight from Dublin, Ireland to Newark, New Jersey. The pilot decided to turn the plane back to Dublin so she could get emergency treatment. (Full story of incident here.)

The girl had no history of food allergies, and began reacting about two hours into the flight. Her mother said she had eaten a cashew. A fellow passenger told a media outlet that the girl’s face was highly swollen and she was in distress. The girl was given two epinephrine injections in flight and, once the plane landed, she was taken to hospital and fully recovered.

A second case of anaphylaxis in the skies occurred in mid-August on a Ryanair flight from the Canary Islands to London. A 4-year-old girl with a known nut allergy was on board, and the crew made an announcement to passengers to refrain from eating nuts. However, about 20 minutes into the flight, the girl began scratching at her cheeks, then her tongue swelled, her lips began to blister and she began to have breathing distress.

The girl’s mother told media that her daughter briefly lost consciousness on the flight. After an announcement  requesting medical personnel, an ambulance driver on board offered to inject the girl with her auto-injector, after which she regained consciousness and her condition improved. It was the first time the girl had required an epinephrine shot.

It was reported that a man had been sitting four rows in front of the family eating nuts, despite the crew’s PA requests that passengers refrain from eating nuts because of an allergic passenger. It has not been confirmed that this was the cause of the reaction, but Ryanair banned the man from its flights for two years.

These incidents are alarming for the food allergy community. Allergic Living asked Dr. Matthew Greenhawt, who has published two studies on airlines and allergies, for his views on these cases and flying with allergies in general.

With a food allergy to peanut or tree nuts, is it likely for an allergic reaction to occur from one person opening a bag of nuts on a plane, four rows ahead?

Dr. Matthew Greenhawt: The short answer is that it is highly unlikely for a passenger to inhale nut protein from someone consuming nuts a few rows in front of him/her. There is no evidence that has been able to show that such dust circulates. Five studies in the past 10 years have addressed this concept and found the following results:

a) Close range (12 inches) exposure to inhaling peanut butter resulted in no reaction in severely reactive peanut allergic subjects.

b) Peanut dust could not be detected in the air from stomping on peanuts on the floor or from opening an airline-style bag. If a scientific measuring tool is placed an inch or two above peanuts being de-shelled, dust can be briefly detected in low quantities (300 micrograms), but only while the item is being de-shelled. As soon as the shelling stops, dust is no longer detectable. This implies that the dust settles, rather than circulates.

c) Peanut butter and peanut dust are both easily cleaned from hands and surfaces using a variety of commercially available cleaners.

Smelling pre-roasted nuts being re-warmed on board is similar to the smell of peanut butter (which was proven to not cause reactions). This may not make concerned passengers more comfortable, but most experts agree that there are no active proteins involved in breathing in the aroma of re-heated, pre-roasted nuts.

Apart from reactions where one eats a contaminated food, airline reactions most likely occur from allergen that may accumulate on surfaces. This we know happens in many different environments. On the plane, without being aware, one could potentially touch a surface that hadn’t been wiped down first, and theoretically ingest some level of allergen.

In fact, from my own studies and studies I’ve reviewed, I’m suspicious that this surface contact may be more of a problem than the air being inhaled. The good news is that pre-cleaning your personal seating area surfaces can reduce the risk of an unintended, unnoticed ingestion.

Is re-circulated air on an airplane likely to contain enough airborne allergens to cause reactions throughout the plane?

Dr. Greenhawt: It is very unlikely that someone would inhale a dose of an airborne allergen. Airflow dynamics for commercial jets actually mandate that there is frequent air-exchange and HEPA filtration of that air. Depending on the type of aircraft, its age, and its make, there are varying levels of air exchange between the cabin and the sky, meaning that there is minimal “re-circulation” of the same air during a flight. A nice explanation for this can be found here.

Have you ever heard of a situation similar to the Ryanair case (i.e. a suspected severe airborne reaction on an airplane)?

Dr. Greenhawt: I have had the opportunity to conduct two large studies of airline reactions, and reactions by inhalation were reported in both studies. Stories of similar types of reported reactions make the news from time to time, are reported to advocacy groups, or can be read about on the Internet. However, it is strongly felt that it is very hard to say with any certainty that the allergen in these situations was inhaled.

Again, there is no evidence to show that peanut or tree nut circulates in the air, as opposed to it quickly settling on surfaces. In such situations, it is likely that there is some unnoticed ingestion of settled dust on a surface through casual hand-to-mouth contact. This type of ingestion may be overlooked when potentially focusing on someone nearby who may be eating a nut-containing item, which may mistakenly be presumed by the passenger to be the trigger.

In my 2012 study, we actually showed a decreased risk of reporting an in-flight reaction associated with wiping down one’s seating area. We feel this is a simple, proactive, and effective strategy that removes residue, thus decreasing the chance of inadvertent contact leading to unnoticed ingestion. However, we also realize that many people still assume or report their child has had an airborne reaction, in spite of the available evidence that this is highly unlikely to occur.

Do you have any other comments about either case, or about flying with food allergies in general?

Dr. Greenhawt: I know that for many peanut- and tree nut-allergic individuals, flying may be a terrifying experience, one that may be avoided altogether. With any highly publicized food allergy incident, the natural tendency is to try to personalize the experience to your particular case. With this recent event, I think United Airlines should be applauded for how this incident was handled. The reaction was quickly identified, the crew involved, the child given epinephrine, and the flight diverted. They did everything they could to help this child, and the reaction resolved. Please keep in mind that diversion is not always necessary, even if epinephrine is given, and is ultimately the captain’s decision on a case-by-case basis.

With flying in general, we recently reported on eight behaviors that seemed to support a lower chance of reporting a reaction. The majority of those with peanut/tree nut allergy fly who do fly do so without incident, and that point that is often overlooked. There is not enough focus on how unlikely a reaction is to happen, especially if one takes the extra effort to be prepared:

1. Have your epinephrine, wipe down your seating areas (and other areas you may touch), bring only your own food and for accommodation, ask in advance.

2. Pre-identify yourself to the crew as this may help with accommodations. If your accommodation is not granted, don’t panic, and don’t argue (arguing with the crew never helps, and may lead to further negative confrontation). There are steps you can take to reduce risk that don’t impact other passengers or crew.

See also:
Air Travel & Allergies: 8 Factors That May Reduce Risk
Airline Allergy Policy Comparison Chart

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