Every Halloween I hear the same collective plea from parents of children with severe food allergies: please be careful of what candy you give out to trick-or-treaters. Most children with food allergies learn at a young age to look carefully at any food that comes their way. But even if they avoid candies with peanuts, for example, many other candies are made in factories that process peanuts. This can still pose a life-threatening hazard to some children. And this is why Halloween is such a scary holiday to their parents.
You can avoid the food issues altogether buy giving away non-food items. Try dime-store treats like temporary tattoos and stickers. (Little bouncy balls, balloons, and novelty erasers are other cute ideas but can be dangerous to kids with latex allergies). I think all parents will appreciate one fewer sugary treat going into their children's bags!