Of all food allergic reactions in the United States, 90 percent are caused by eight foods: milk, soy, wheat, eggs, fish, shellfish, tree nuts and peanuts.
Peanuts aren't really nuts -- they grow below ground and are a member of the legume family.
Some 9 million Americans are allergic to the four foods that cause the majority of severe reactions: fish, shellfish, tree nuts and peanuts.
BALTIMORE, Maryland (CNN) -- Peanuts are as American as baseball -- Americans ate nearly 1.7 billion pounds of them last year, according to the Georgia Peanut Council.
But for those with peanut allergies, even 1/1,000 of a peanut can cause a severe reaction.
The chicken that 15-year-old Robert Bigelow Rubin chose at a bar mitzvah because he thought it was safe was prepared with peanut oil. His night ended in the emergency room.
"I couldn't breathe, and then I started wheezing, and then they called 911," he said.
Food allergic reactions cause an estimated 30,000 emergency room visits and kill 150 to 200 people a year.
Anaphylaxis, the massive allergic reaction triggered in some sufferers, can also be triggered by bee stings, latex rubber and even vigorous exercise.
According to the Food Allergy and Anaphylaxis Network (FAAN), 11.4 million Americans have food allergies.
Reactions can be triggered by even trace amounts of peanuts.
"There are true risks when ... enough peanut protein is really being disturbed. So if people are cracking open peanuts, especially in a confined space, a waiting area of a restaurant, you could have a very severe reaction because there's enough peanut airborne there," said Dr. Robert Wood of Johns Hopkins University.
At least five U.S. airlines have stopped serving peanuts: American, Delta Shuttle (not all of Delta Airlines), Northwest, United, and US Airways.
A study by FAAN and the Mt. Sinai School of Medicine in New York showed the number of children allergic to peanuts doubled between 1997 and 2002.
Jacqui Corba, 15, had her first reaction when she was 2, even though she wasn't eating peanuts herself.
"I was on an airplane flight with my mom, and she ate peanuts and gave me a kiss on my face, I blew up like all over and I was red."
She also had an anaphylactic reaction at school after a classmate opened a bag of peanuts near her.
Many schools now reserve separate tables where no peanut butter is allowed.
The medical community cannot fully explain the phenomenon. But there are theories.
Noticing that developing countries have almost no allergy led doctors to suspect that our society is too germ-free.
"As a country becomes more developed, allergy rises and rises. And the notion there is that in the more-developed countries, you may be getting less exposure to infections and germs and other things that may stimulate your immune system in a direction other than allergy," Wood said. "The more your immune system is kept busy by exposure to germs and infections early in life, the less time it can devote to things like allergy."
Anne Muñoz-Furlong, head of FAAN, says "Perhaps our homes are too clean -- we've done too much to take away the job of the immune system. We don't have parasites, a lot of the childhood diseases you vaccinate and don't have, so maybe for some people, the immune system is looking for something to do and decides, 'Aha, I don't like milk' or 'I don't like peanuts,'" and the body then attacks the food protein as if it were an enemy invader."
Another theory researchers are looking at is that children are exposed too early to peanuts.
Adding to the confusion is that in countries like Indonesia and Thailand, where peanuts are ubiquitous, there is virtually no peanut allergy, leaving the experts to concede they really don't know for sure why food allergies are on the rise.
For now there is no cure. Doctors can only prescribe strict avoidance. But that's not easy as so many candies might contain traces of peanuts inside.
Brandon Katona, a 13-year-old allergy sufferer, explains "you never know where peanuts ... will show up in anything you eat or touch."
Epinephrine offers treatment for a reaction. Those with serious food allergies carry auto-injectors that contain epinephrine obtained by prescription that they can inject quickly to the thigh.
Without epinephrine, these reactions can lead to a sudden drop in blood pressure or even death and it can happen fast.
Wood lost three teenage patients who had anaphylactic reactions. One had eaten a baked good, another Chinese food, the third a piece of candy. None had epinephrine available.
"People shouldn't be dying of allergic reactions," he said. "Because if you get epinephrine in a timely way after reactions, we can be very reassuring to our patients that they are not going to have a fatal reaction ... and timely means within a few minutes."
But even experts inadvertently expose themselves.
Wood, who has had a lifelong allergy to peanuts, has rules about what he eats. And he doesn't accept baked goods from others.
But he made what he thought was a safe exception and accepted a homemade cookie from a colleague, another expert on food allergies, who assured him it was safe.
"You know quickly, typically, if you're having an allergic reaction -- you get an immediate sensation in your mouth that you've been exposed to something," Wood said. "So I knew it within seconds, literally."
His colleague had used the same spatula and maybe cookie sheets in making one batch of peanut butter cookies and a second batch of peanut-free cookies that he gave to Wood.
"But that amount of contamination just from a spatula when it comes to peanut allergy, is enough to cause severe reactions," he said.
It took five shots of epinephrine to stop Wood's reaction.
Michelle Risinger, 20, is allergic to peanuts and tree nuts like pistachios. She once ate a cookie in her dorm room she was told had white chocolate chunks, which really turned out to be macadamia nuts.
"Within seconds, my throat started closing. It was tingling. I started to get hot all over. And I went to my desk drawer, used my [epinephrine auto-injector] and I called 911."
Even though she injected herself, the reaction wasn't over.
"As the ambulance was pulling up, my throat started closing again, and by the time we got to the hospital, which was maybe a five minute ride, I was having severe respiratory trouble," she said.
She ended up spending the night in intensive care.
Risinger and a boyfriend had earlier found out about the severity of her allergy the hard way.
"I've had a reaction from kissing once ... he started kissing me, and my lips started tingling, and immediately I was like, 'we have to stop, and I need to take Benadryl.'"
To avoid what literally could be the kiss of death, Risinger gives her dates a choice: It's either peanuts and nuts, or her.
CNN senior medical correspondent Dr. Sanjay Gupta and senior producer Sharona Schwartz contributed to this report.
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