For the growing number of parents of children with peanut allergy, back-to-school can be a particularly stressful time. Exposure to even tiny amounts of nut particles - residue on a desk, a book, or a container - can cause a potentially life threatening reaction. Nutrition expert Leslie Beck is here with tips for packing safe meals and snacks.

Q: Why do so many children have a peanut allergy these days? Is it on the rise?

You're right, a generation ago we rarely heard about peanut allergies and there were certainly no such thing as nut-free classrooms. According to the Allergy/Asthma Information Association, one out of every 150 school aged child is allergic to peanuts or nuts, allergies that can be severe and lifelong. Among those diagnosed with peanut allergy, the majority - 80 percent - will have it for life.

The incidence of peanut allergy is said to have doubled over the past decade for reasons that remain unknown. The rise parallels the rise in all allergic diseases such as asthma and atopic disease in children. There are numerous theories to explain the increase; however, the theory that seems to have the most support from studies is the "Hygiene Hypothesis." The Hygiene Hypothesis states that the more hygienic a society is the more allergic people are as well. Studies suggest that the immune system in early infancy is primed to recognize and fight infections. In the absence of infections, the immune system begins to target innocuous items in the child's diet and environment

Q: If a child has a peanut allergy should he avoid all nuts?

Individuals with peanut allergy are not necessarily allergic to other nuts and vice versa. That's because peanuts don't come from the same family as nuts such as almonds, walnuts, cashews, pecans, pistachios and hazelnuts. Peanuts come from the legume family (peas, lentils) and grow in the ground whereas other nuts grown on trees.

It's estimated that 25 to 35 per cent of people with peanut allergy are also sensitive to tree nuts. If a child is allergic to one tree nut, it's recommended that all tree nuts and peanuts be avoided due to the risk of cross contamination.

Q: What are the symptoms of a peanut or nut allergy?

While all food allergies cause uncomfortable symptoms, peanut and nut allergies are especially troublesome because they often result in more severe reactions than other food allergies and after exposure to only trace amounts of the offending food.

Like other food allergies, peanut and nut allergies are caused by an over-reaction of the body's immune system to otherwise harmless proteins. Symptoms can include hives, skin rash, runny nose, coughing, wheezing, sneezing and itchy-watery eyes, stomach pain, vomiting and diarrhea.

Peanut and nut allergies can also cause anaphylaxis, the most severe form of allergic reaction involving several parts of the body. Anaphylactic reactions occur almost immediately after exposure and are characterized by swelling, breathing difficulty, abdominal cramps, and vomiting. If not treated immediately, death can result.

Q: With so many nut-free classrooms the norm these days, peanut and nut allergies affect even parents whose child is not allergic. Any tips for packing nut-free snacks and meals?

The only way to prevent a reaction is complete avoidance of all peanuts and nuts, including all foods that contain them and their derivatives. In an effort to protect children with severe food allergies, many schools have designated peanut-free or nut-free zones or classrooms, and some have declared the entire school nut-free.

For parents who are new to packing lunches or snacks for a nut-free classroom, the learning curve can be steep.

Reading labels and ingredient lists is key. Read the ingredient list every time you shop since manufacturing and packaging practices can change without warning. A product that was safe last week may not be safe this week. Keep in mind, though, that peanuts, tree nuts and their derivatives can be disguised by other names on ingredient lists.

Peanuts in disguise
 Arachis oil
 Beer nuts
 Goober nuts, goober peas
 Ground nuts
 Mandelonan nuts
 Nut meats

Q: What foods should be avoided?

Common foods that contain peanuts and tree nuts include peanut and nut butters, granola bars, cereal bars, cookies, pastries, ice cream, frozen desserts, energy bars, salad dressings, cereals, granola, grainy breads, and marzipan.

Refined peanut oil should not contain any peanut protein and is unlikely to cause an allergic reaction. Unrefined, or cold pressed, peanut oil may have peanut proteins and could trigger a reaction.

The statement "may contain traces of peanuts or nuts" means the product is risky and should be avoided.

Do not buy any food that doesn't have an ingredient list such as bulk foods and bakery goods. Avoid imported chocolate bars which may contain traces of peanuts or nuts.

Nut-free shopping: Avoid
 Unrefined peanut oil
 "May contain traces of nuts"
 Bulk foods
 Bakery goods
 Imported chocolate

Don't assume that all formats and sizes of a nut-free product are safe. For instance, a regular size chocolate bar might be labelled peanut-free, but the snack size version could carry a "may contain traces of peanuts or nuts" warning. Some foods such as chocolate candies and sunflower seeds are often made on equipment that's also used to process peanuts and peanut-containing foods.

If you're unsure whether a product contains peanuts or tree nuts, contact the manufacturer for ingredient information.

Q: Tell us about some of these nut-free products for school lunch boxes.

It is getting easier to find a variety of allergen-free foods in mainstream grocery and natural food stores across the Canada

Dare Foods (Canada) has declared its manufacturing facilities nut-free and peanut-free (products containing nuts are made outside the facility.) As a result, you'll see Dare's peanut-free logo on 29 products including cookies, crackers, candies and fruit snacks.

Quaker Chewy granola bars are also made in a peanut-free plant. (Chewy Dipps, Chewy Yogourt and Chewy Trail Mix are not peanut-free.)

Enjoy Life Foods offers allergen- and gluten-free cookies, granola, snack bars, bagels, and trail mix. You'll also find Nonuttin' Foods granola bars and trail in natural food stores. If you're looking for an alternative to peanut butter, NoNuts Golden Peabutter is available in grocery stores across Canada (it's made from golden brown peas).