2. Avoid serving nuts and using nut oilssesame, peanut, etc.while cooking because for children with severe nut allergies, oil traces left on countertops can set off a reaction, even without eating the food in question.
3. Know your ingredients. Be sure that you and whoever is serving food know the ingredientsall of themof what's being served. They're not always obvious - milk can be hiding in veggie dogs and soy is contained in many prepared foods. if you're serving catered foods, be especially vigilant about ingredients.
4. If a food is at all questionable, be sure to let your guests know.
5. Be sensitive to sweet tooths. children are likely to be especially disappointed if they can't eat dessert. Try to serve at least one that fits the child's dietary requirements.
6. Don't make a big deal out of the child's allergy. Some children are sensitive, or go through stages where they are uncomfortable feeling "different" from everyone else. Fill the child's parents in on ingredients and alternatives and let them gauge how to handle with their children.
7. Avoid or adapt children's games involving food so that the allergic child doesn't feel left out. (e.g., don't use egg matzoh for "hide the afikomen" at Passover when a child who is allergic to eggs is present.)
8. If you really want to make a family feel welcome, call in advance and ask if there's anything you can do to make the holiday gathering easier for them.