Chunky or smooth? That was once the biggest debate around for parents and children surrounding peanut butter. Now, parents are faced with a more threatening decision: when to introduce foods like peanut butter into their child’s diet, if ever.

According to The Allergy Report, six foods cause 90 percent of food allergy reactions in children. They are: milk, eggs, peanuts, wheat, soy, and tree nuts (such as pecans and walnuts). Many children outgrow allergies to eggs, milk, and soy – but allergies to peanuts, tree nuts, fish, and shellfish often continue into adulthood. And since these allergies can carry a risk of anaphylaxis – a severe, life-threatening reaction that involves swelling of the air passages – parents are understandably concerned.

About 2.2 million school-aged children, 4 percent of U.S. students, have food allergies, and 3.3 million Americans of all ages are allergic to peanuts or tree nuts, according to the Food Allergy and Anaphylaxis Network (FANN). And that number is on the rise. The peanut butter and jelly sandwich may have been a staple when you went to school. But since then, childhood peanut allergies have shot up significantly. According to a study by FANN, they’ve doubled just in the years between 1997 and 2002 alone.

But why? While there are no proven facts behind the increase, there are some real theories. One such theory is the “hygiene hypothesis.” The premise is that because people live in such a hyper-clean environment, using anti-bacterial soaps and wipes whenever possible, children simply aren’t exposed to bacteria that would otherwise strengthen their immune systems. Therefore, when a complex protein such as a peanut is introduced into the child’s system, the body thinks it’s an enemy and tries to fight it – and that fight is the reaction.

A growing number of doctors think that if you wait and let your child’s immune system grow and develop more thoroughly before introducing peanuts, then the body may not be triggered to react to it, or the reaction may be less severe.

Another theory behind the rise in peanut allergies is that more women are eating peanuts while pregnant or nursing. Additionally, it’s possible that children are becoming more sensitive by coming into contact with foods that have been contaminated by traces of peanuts. A study by the Food Standards Agency found that 56 percent of pre-packed food items had the potential to trigger a peanut allergy.

So what is the best defense? Obviously, if you know that your child has an allergy, don’t give them any foods that may cause a reaction. If you don’t know your child’s sensitivities yet, find out whether you have a family history of allergies. If so, do not eat peanuts while pregnant or nursing. But regardless of your history, some experts believe keeping all potentially nut-tainted foods away from your child’s diet for the first few years of life is a good idea.

Allergies are not the end of the world. But if your child has them, work with his school to ensure a safe environment. While some schools are outlawing peanut butter altogether, some are not. As a safety precaution, ask your child’s school whether the nursing staff has Epinephrine on hand. Epi-pens are an emergency treatment for anaphylaxis and could save your child’s life.

The stress of allergies can be burdensome – both for the parents and for the child. It’s hard to skip an ice cream sundae at a friend’s birthday party because you can’t eat the peanuts on the top, or to be the kid in school responsible for getting PB and J outlawed. Try to educate your child about allergies without scaring him. Allergies don’t have to ruin a child’s life – they just change it a bit.