If you have egg allergies, your immune system overreacts whenever you eat eggs. It mistakenly thinks egg proteins are harmful, so when it identifies egg proteins in your body, it sends out an antibody called immunoglobulin E to combat those allergens. The antibody then sends out chemicals to fight off the "invaders." You notice the fight between your immune system and the eggs when you suffer from allergic symptoms; they're the result of the chemicals doing battle in your body.
The best way to avoid allergic symptoms is to avoid eggs and egg proteins. Clearly, this means not eating hard-boiled eggs, omelets or scrambled eggs. But it also means keeping your eyes open for foods with eggs as ingredients. On the packages of store-bought foods, manufacturers are required to put a line that warns people with egg allergies when a product contains eggs or was made in a facility that uses eggs. This way, you don't even have to bother reading the ingredients list. If you do decide to read the ingredients listed on a package, look for words like albumin, globulin, lecithin, livetin, lysozyme, simplesse, vitellin and anything that starts with the prefix "ova" or "ovo." All of those ingredients can contain egg proteins.
Homemade foods can contain eggs too, so ask your friends before you eat at their house. The same applies to dining out at restaurants. Something called cross-contamination can be a problem for highly allergic people; when the same cooking utensils are used to make foods with eggs and without, the eggs from one might get into the other. Although it might sound weird, some people with egg allergies are also sensitive to certain shampoos, medications, cosmetics and finger paints that contain eggs, so it's best to verify ingredients when you can and always be prepared in case of an allergic reaction.