Food allergies are on the rise among children, affecting 4 percent of U.S. kids age 17 and younger and up 18 percent in the past decade, according to a 2008 report from the national Centers for Disease Control and Prevention. Eight foods accounted for 90 percent of food allergies: eggs, fish, milk, peanuts, shellfish, soy, tree nuts, and wheat.

Researchers are perplexed by the reasons for the increase in food allergies. But for parents of kids with allergies, the bigger concern isn’t the cause, it’s how to keep their child safe. Children with severe allergies can go into anaphylactic shock, a severe reaction marked by swelling of the throat and tongue, among other symptoms.

Parents should make a plan with the school as soon as possible if their child has known allergies, says Dr. Karen DeMuth, a pediatric allergy and immunology specialist with Children’s Healthcare of Atlanta. “Good communication, that would be my first recommendation,” she says of parents getting ready to approach their child’s school about an allergy.

Although it’s important to talk to the principal and to your child’s teacher, the most important people who need to understand your child’s condition are in the cafeteria, not the classroom, DeMuth says. “The ones who serve the food and give out the food—they need to be educated on how to avoid the food and how to end the reaction.”

Take one of the most commonly recognized and potentially severe allergies: peanuts. A cafeteria worker might make peanut butter sandwiches for most students and then a ham-and-cheese sandwich for a child with a peanut allergy. But what if she uses the same knife to cut the ham sandwich that was used for the sandwiches made with peanut butter? A severely allergic child could have a reaction. Or someone might bake a batch of sugar cookies after baking peanut butter cookies so that kids with allergies can enjoy a treat. An allergic child could be at risk, however, even if the cookie sheet has been washed after each use.

Even parent volunteers need to be educated about allergies. If a parent passes out trail mix containing peanuts as a class treat, she might pick out the nuts for a child who says he’s allergic. But the fruit might be contaminated, triggering a reaction.

Some children are so sensitive to peanuts, they can’t even sit next to another child eating the food. Some school officials have designated a table or section of the cafeteria a peanut-free zone. Other schools have banned peanut products altogether.

Children with severe allergies need to keep an EpiPen (an epinephrine shot) available in case they accidentally ingest the food they’re allergic to and go into anaphylactic shock. Epinephrine works to counteract swelling and other symptoms related to anaphylaxis, and so the injection should not be kept solely in the school clinic, the principal’s office, or a locked cabinet that only one person has access to, DeMuth says. “The pen should be with the child or in the vicinity of the child.”

As soon as a child is old enough, she should know how and when to use the EpiPen, as should the adults who take care of her. “Allergists will train the parents and caregivers on how to use it,” DeMuth says.

The most powerful weapon against an allergic reaction is education. It’s important to teach children to read food labels carefully. “A child should be aware of what their food allergy is and how to avoid it,” DeMuth notes. Still, most reactions happen away from home, where food labels are less likely to be available for inspection; food allergies claimed about 150 lives in 2007, and everyone knew about the allergy and the importance of avoiding the food, she says. Children need to be taught to be assertive in telling adults about their allergies and to avoid foods that might put them at risk, even if it means passing up birthday cake or some other treat.

Besides the common allergies, some children may have reactions to foods not usually associated with allergies, such as pineapple or peaches. “[For] almost any food, there is someone who is allergic to that food,” DeMuth says.

Allergies usually surface before a child is old enough to start school, and most children are only allergic to one or two foods, though some may be allergic to a wide variety. Food allergies often go hand in hand with other medical conditions—children with food allergies are two to four times as likely to have asthma and three times as likely to have skin and respiratory allergies, for example. Many children will eventually outgrow their food allergies.