I think the hardest part of having a food allergy is explaining it to other people. Many people get confused between an intolerance and an allergy. The two are often used interchangeably, which is very incorrect. Many people don't understand than an allergy is more than a discomfort. Many people don't understand that allergens cause reactions in the smallest amounts.
Here's a really well written (and easy to understand) article from the Mayo Clinic that you can share with friends, family, school, etc.
With that said, I also caution reading articles, message boards, and blogs online looking for the truth. I often find that many don't distiguish between the two. Always consult a doctor for major issues or questions you really need the answer.
A little update
4 years ago