There are few things more frightening than experiencing a medical crisis at 36,000 feet.
Imagine being trapped in a tin can, high above the Earth, the nearest hospital hundreds or thousands of kilometres away.
You are dependent on the first-aid skills of a flight attendant or, if you're lucky, a physician or nurse who happens to be on the plane.
It is a fear that people with severe allergies know all too well - and doubly so because many airlines stubbornly insist on selling and serving foods that can trigger the most severe allergic reactions.
In its current edition, the Canadian magazine Allergic Living has highlighted this issue superbly in a cover story titled Plane Truths.
The magazine has also launched a "reduce the risk" campaign to put pressure on big airlines such as Air Canada and WestJet to make the skies safer for the growing legions of children and adults with severe allergies.
"Flying is a fundamental part of modern life, and the allergic have a right to do it safely - like everyone else," says Gwen Smith, editor of Allergic Living.
After all, what goes on a plane is a microcosm of the challenges of the real world for allergy sufferers.
This is not a group of nutty radicals asking for the world, but forced-by-circumstances activists looking to protect themselves and their children from real danger.
Essentially, the write-in campaign is asking the airlines to develop clear, consistent and articulated policies on allergies to minimize the risk of in-flight reactions.
"We're not asking for the allergy police. But there's a snack-nut culture on the plane that needs to change," Ms. Smith said.
In fact, the only place where people are exposed to more food allergens is in baseball stadiums.
No one is suggesting that the world - or every airplane in the world - can be made nut-free or allergen-free.
But the current attitude of airlines, which can be summed up as "hey, it's not our problem," is simply not acceptable.
More frustrating still - and more dangerous for allergy sufferers - is that policies are inconsistent.
Anaphylaxis is not to be dismissed casually: It is a severe, life-threatening systemic allergic reaction triggered by exposure to one or more antigens, including foods, insect stings, drugs or latex products. Up to 8 per cent of children have food allergies, and allergies to peanuts and tree nuts among children have doubled in the past five years.
There are about one million Canadians and 11 million Americans with severe allergies, and airlines that ignore this reality are toying with disaster.
Many airlines, to their credit, have stopped serving peanuts after research showed that peanut dust was readily circulated by airplane ventilation systems and that peanut oils could be found on many surfaces.
But airlines are a long way from being nut-free.
Snacks that are distributed now include cashews and other nuts, and sesame concoctions - highly allergenic foods, particularly for children.
Airlines have cut back drastically on the meals they serve, but paradoxically this may have increased the risk of exposure as passengers bring all kinds of foods on board, from sunflower seeds to pad Thai.
A new study showed that about one in 10 people with allergies suffer a reaction while on a plane, a frighteningly high number.
The folks at Allergic Living are not suggesting Draconian measures such as banning potential allergens. Rather, they are calling for more education and better communication by airlines.
A simple announcement by flight attendants that some people are severely allergic to nuts and a request to refrain from eating them on board could go a long way.
And surely doing away with the distribution of salty snacks entirely - or, better still, offering travellers a bit of fresh fruit instead - would not cause airlines any great hardship.
The oft-stated argument that doing so would be unfair to other customers beggars belief as these same airlines have managed to do away with other "staples" such as pillows, blankets and leg room.
When it comes to items for sale, it would be no more onerous for airlines to sell nut-free chocolate bars than potentially allergy-triggering ones.
Reducing risk is not the sole purview of the airlines. People with severe allergies have responsibilities as well.
Allergic Living, along with its cover story, offers up a number of tips for allergic travellers.
These include calling ahead to learn airline policies, wiping down seats and trays, packing their own food to avoid nasty surprises and, of course, carrying medication to treat allergic reactions (epinephrine in auto-injectors, known commonly by their brand names such as EpiPen and Twinject).
The magazine also urges consumers to follow up with airlines after travel - praising them when they are helpful to allergic travellers and complaining when they do not, including writing to the company itself and the regulator, the Canadian Transportation Agency.
The CTA made headlines recently when it ruled that airlines must accommodate travellers who are disabled by obesity in the same manner as others with disabilities.
Those with severe allergies must be accommodated, too, especially because they risk not only discomfort but death.
Food allergy flying tips
BEFORE YOU FLY
Call the airline or travel agent to check on allergy policies before you book.
Tell the reservation or travel agent about your allergies.
Book a flight that's earlier in the day - planes are cleaned overnight.
WHEN YOU FLY
Tell everyone you deal with - check-in agents, staff at the gate, flight attendants - about your child's or your allergies.
Wipe down the seat, tray table and armrests and cover the seat with a blanket. Bring your own food, and make sure you have enough in case of delays.
Keep medication with you.
If someone nearby you is eating food that is dangerous to you, politely explain your situation and ask if they would stop.
If you are reacting to something, tell the flight crew.
AFTER YOU FLY
Let the flight crew and airline know whether you had a good or bad experience, noting that it will affect your future plans to travel with the carrier.
If you have a problem, file a complaint with the Canadian Transportation Agency.
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