Food allergies are more common in children than adults. In children ages 1 – 3, up to 6% have true food allergies. In addition, 133 million Americans suffer from food intolerances, and limit their diets as a result. Symptoms of food allergy can be as mild as stomach upset or a skin rash, and as serious as anaphylactic shock, a potentially fatal reaction. These foods are responsible for almost 90% of food allergies: dairy/casein, tree nuts/peanuts, fish/seafood, wheat/gluten, soy, and egg. Peanuts and seafood account for the most anaphylactic reactions. For more information food allergies and intolerances, see the links at the end of the article.
Parents of twins with food allergies often find that the twins have different food allergies, or even that one twin has food allergies and the other does not. The tendency to develop food allergies is genetically based, but even identical twins will often not share specific allergies. For example, one may be allergic to dairy, and the other to peanuts. So what does a parent do when one twin is allergic and the other is not, especially when an exposure to an allergen could cause a serious reaction?
If the twins are young, most parents feed both a diet safe for the allergic child. "My twin girls lick each other, kiss each other, handle each others toys, etc... I would have never made it this far if I had one eating the others allergens," says Denise, a mother of twin girls. Beth, a mom of identical twin girls, agrees with this approach, and provides another rationale for limiting both twins' diets to safe foods. "They are identical and even though we have no problem telling them apart from the front, a lot of friends and caregivers cannot tell them apart."
Some families are comfortable allowing the non-allergic twin to eat foods containing allergens when the other twin is not present, to avoid hurt feelings or arguments. However, in the case of severe peanut allergies it is usually best for anyone who will come in close contact with the allergic child to avoid eating them altogether. Peanut oil can persist on surfaces, hands, and lips for a long time, and can cause a reaction hours after being eaten if the affected twin is touched or kissed by the person who ate the peanuts, or even if the affected twin touches an object that person touched.
As children with food allergies mature, some of them will grow out of the allergy. Those whose allergies persist learn to read labels, ask questions, and accept their diet limitations (often more readily than the adults around them). It's just "life as usual" for them. In the case of twins, most parents I interviewed believed it was better to wait until both twins were mature enough to understand how to manage food allergies before allowing a twin to eat foods that weren't safe for the other. However, if one or both twins has a severe allergy, likely to cause anaphylaxis, it is probably prudent for both to avoid those allergens in and out of the home.
Food Allergies Info Sheet from Duke University: http://www.dukehealth.org/dr_clements/food_allergies
Kids With Food Allergies (support for parents): http://www.kidswithfoodallergies.org/index.php