About Egg Allergen
Dr. Antony Ham Pong, MD FRCP, is an Ottawa-based allergist who responds to questions from an AAIA member about egg allergen.
My school-age child is allergic to egg. Do airborne food particles pose a risk?
You can be assured that under normal circumstances anaphylaxis to airborne egg or food particles is very rare. I am not aware of any such reaction to egg but there have been reported allergic reactions to airborne fish, shrimp, and probably peanut particles, and probably milk and wheat. So the same could be true of egg. However an allergic reaction to egg or any other food will not occur because someone is eating it in the classroom or vicinity of the allergic person. The main reason for advising that the allergenic food not be brought into a classroom is the potential for the allergic child to accidentally ingest some by sharing food. Secondary reasons (less likely to cause anaphylaxis because of the smaller quantities involved) are cross-contamination of common objects such as desks, toys, etc.
So when can egg or other foods become airborne and cause an allergic reaction or anaphylaxis?
- Boiling or cooking the food in the immediate area. Foods like peanut and egg do not evaporate into the air at room temperature - you may smell it but what you smell are the volatile essences and not the proteins which are what causes allergic reactions. So to get the allergenic proteins into the air, you need to boil or cook the food so water vapour in the form of steam carries small particles of the egg or other food into the air. Then the allergic person inhaling it can have an allergic reaction. This has been reported for fish, and in shrimp handlers and I have seen patients reacting to milk in this way. So cooking egg out of the shell in the immediate area may cause allergic reactions by the airborne route. Egg powder can be found in some household packaged powdered mixes such as pancake or waffle mix, some soup and sauce package mixes and these should not be brought into the classroom since there is a risk that the powder could be inhaled.
- Inhaling the food when it is in fine dust like particles. For example, wheat flour can cause allergic reactions in wheat allergic people who try to bake with it. The same could be true for peanut allergic people who walk into sports bars where there are peanut shells being crunched on the floor and fine peanut dust is in the air (I don't know if this has been reported but can likely occur); This would also apply to airplanes - if a lot of people open their pressurized peanut bags, the fine dust from all the bags goes into the air and can cause allergic reactions. And a few people who work in factories can become allergic to the food dust they are inhaling. I have a patient who developed an allergy to inhaled egg when working at a chocolate factory handling powdered egg. Same could happen with powdered milk. And health care workers can become allergic to psyllium (Metamucil used for constipation) when they handle the psyllium powders and give it to patients - this has caused anaphylaxis.
Hope this helps you. Remember that no matter how severe the egg allergy is, being in the same vicinity of egg which is not under the conditions of 1) or 2) above does not cause allergic reactions.
from Allergy & Asthma News, Issue 2 2007