Recently, I contributed a short column to our local paper about hosting food-allergic guests at summer parties. My piece was geared to the non-allergic, so here's a slight reprise for use by all of us who deal with food allergies every day.
Talk about it. When you reply to an invitation, notify your hosts immediately about any food allergies or dietary restrictions. It's nice to give them advance notice so that they can tailor the menu or ask you to bring a dish.
Bring the dessert. Most people with food allergies have to avoid desserts from bakeries or even other people's kitchens because of cross-contact concerns or because they can't eat the ingredients--nuts, eggs, wheat. Offering to bring at least one of the sweet treats ensures that your family members will be able to enjoy dessert with everyone else.
Beware of double-dipping. A perfectly "safe" food can become allergenic if the same utensils used for one dish are then used in another. Buffets can become danger zones for this reason. If you are invited to a buffet, either ask to serve your child first or bring your child a separate main dish that only they will eat.
Consider the grill. Grills can become a food allergy nightmare due to marinades containing peanut butter, nut oils or dairy items and/or potentially allergenic proteins like seafood. (Or hamburger buns, if you've got wheat allergy or celiac disease). You might want to invest in a Smokey Joe (small size BBQ) to tote along to a party. That way, you can grill away without worry.
Own the allergy. Don't be afraid to bring your own food or to share your allergy concerns with your hosts. An upbeat explanation of why your child (or you) can't eat a particular food beats staying at home. In the end, it's more important that you enjoy time with friends and family than what you eat while you're there.