It wasn’t stage fright that made him dizzy and nauseous.

It was the after-party.

Eleven-year-old Jacob Sawyer was celebrating his performance as Bilbo Baggins in his church’s rendition of “The Hobbit” with a tasty treat.

“I ate this cookie-dough energy bar, a Larabar,” he said, “and I was immediately retching. Five minutes later, the hives came. It was the worst thing you can possibly imagine. It itched all over.”

His mom gave him Benadryl and rushed him to the emergency room.

“They knew it was a food allergy,” Jacob said, “and they thought it was most likely cashews. We brought the wrapper.”

Skin tests revealed he was allergic to two tree nuts, cashews and pistachios.

“I’m anaphylactic,” he said.

Anaphylaxis is a serious allergic reaction that can be life-threatening.

He now carries an EpiPen, reads the fine print on food labels and dares to eat only at restaurants passing extensive menu scrutiny.

Life sure was easier before the Larabar.

In the year following his allergic episode, his parents, Lisa and Michael, have studied everything they can about food allergies. It fits with their passion for learning. This is a family that plays trivia games at the dinner table. Younger brother, Nathan, is already a whiz at age 8.

There’s still a lot to learn.

“Part of the problem is they just don’t know what the next reaction will be like,” his mom said. “It’s not anything to play around with. The first time I went into the supermarket after finding out all this I had a panic attack.”

One reason the allergy wasn’t detected sooner was that Jacob didn’t really like nuts, so he rarely ate them.

There were a two previous minor incidents where he got sick after eating trace amounts of cashews from cross-contact in curry chicken and fried rice, but an allergic reaction wasn’t suspected.

“One time everybody was having the stomach flu and another time it seemed kind of random,” his mom said. “Looking back, we could piece it together.”

He is not allergic to peanuts, which is more common and even rates special peanut-controlled seating at some Mariners games.

Dr. David Jeong, a Virginia Mason Medical Center allergy specialist, said about 1 percent of children have a peanut allergy, about double the number with tree nut allergies.

“In children, the more common allergies are to milk and eggs,” Jeong said. “Most kids outgrow these. Children typically do not outgrow nut allergies.”

Jeong is on the advisory board of Seattle Food Allergy Consortium, a collaboration among the University of Washington, Seattle Children’s Hospital, Virginia Mason, and the Northwest Asthma and Allergy Center.

“The four of us came together to create a super group to pool resources to be able to get involved with critical research trials,” Jeong said. “Together, we could pool all our resources and get things moving.”

One trial involved a skin patch for peanut allergies.

Jeong said allergy symptoms include rashes, stomach upset, vomiting, diarrhea, sneezing, itchy eyes, coughing and difficulty breathing.

“It usually ends pretty quickly, within minutes,” he said. “If you’re seeing that kind of pattern, that’s your tip-off.”

A diagnosis using a skin test or blood test can be done at any age.

Allergies, while serious, typically aren’t deadly.

“There are about 100 fatal reactions from a food allergy a year,” Jeong said. “It’s not happening left and right.”

It’s enough to keep Jacob armed with an epinephrine injection device, just in case. It doesn’t stop him from going to Boy Scout camps or spending the night with his friends.

“I worry all the time when I say it’s OK to go somewhere or to eat something,” his mom said.

Jacob worries more about his Star Wars collection than his tree nut affliction.

“You just grow into it. For the first few weeks, you kind of gripe about it, but you get used to it,” Jacob said. “It’s nothing real big. There are people with cancer and all that stuff. You feel how lucky you are.”

It has improved his diet.

“I can’t have pretty much 90 percent of the sweets I used to have. It has made me much healthier,” Jacob said.

Many restaurants are off limits because of possible cross-contact during processing or cooking. These include some pizza places.

“There is cashew pizza. I’m not joking,” Jacob said. “Indian food is pretty much out of the question.”

Most ice cream parlors got the boot.

“I used to love Baskin-Robbins,” Jacob said, longingly.

Can’t go to Dairy Queen, either: “Cashew Blizzards.”

A safe haven is Revelations Yogurt and Dessert Bar in Edmonds, where he said the owner labels everything.

“It’s hard, especially at school when they have treats,” Jacob said. “I think the easiest part for me is that I have a lot of friends who are really nice to me about it and that helps a lot. They’re good to me, especially the moms. They are really nice. We have good support.”

More on food allergies

For more information from the Seattle Food Allergy Consortium, go to www.seafac.org.

Peanut-controlled Mariner games

Fans with peanut allergies can take themselves out to the ballgame without fear of peanuts and Crackerjack. The Mariners will have peanut-controlled seating at 7:10 p.m. July 22 vs. the New York Mets and at 7:10 p.m. Aug. 8 vs. the Chicago White Sox.

There will be about 200 seats available at each game in Sections 313, 314 and 315.

No peanuts or peanut products will be allowed in those sections. Concession stands closest to the sections will not sell any food with peanut products.

Seating sections will be thoroughly cleaned before the game to remove as many traces of peanuts as possible.

Peanut-controlled isn’t peanut-free. Peanuts will be present in other areas of the open-air ballpark. Tickets can be purchased online for $11. For more information, go to www.mariners.com/nopeanuts.