Airborne allergies: Can you have an allergic reaction to smelling a food?

The short answer is no. You cannot have an  allergic reaction to the smell of a food. This does not mean that airborne allergies are not real, but the reaction is to to airborne food particles rather than the smell. 

Often when airborne allergies get reported in the media, we are told someone reacted to the smell of the food. I understand, as an ex-journalist, that they want to simplify the situation and it makes for an easier headline but it is factually incorrect.

What is the difference between the smell and airborne food particles?

To have an allergic reaction to a food, your body needs to come into contact with the food proteins. These are not released in the smell of a food. The proteins only trigger airborne allergies when the food is cooked or disturbed in a way that makes tiny food particles release into the air.

This means that the majority of people with food allergies, even anaphylaxis, can smell peanut butter, be near someone eating an egg sandwich or walk past the fish market without any real risk.

When do food particles trigger airborne allergies?

Food particles usually become airborne in three main ways:

• During certain cooking processes like frying or boiling, when the food is dispersed and miniscule amounts can break off into the air.

• During food preparation when milk is frothed or wheat flour is used and distributed into the air.

• When food is disturbed and releases particles – so when a bag of nuts is opened and dust escapes into the air nearby or when seafood is cracked and juices spray out.

How common are airborne allergies?

It is difficult to say how common airborne allergies are as some people may be susceptible but never in a situation where they are affected. Severe, anaphylactic reactions are very rare. People are more likely to experience watery eyes, itchy throat or a slightly tight chest without symptoms progressing any further. Usually, when people leave the area their symptoms will subside. 

How can I avoid an airborne allergic reaction?

Most the time it is safe to be around people eating or cooking the food you are allergic to. It is sensible to avoid situations which present more of a risk like seafood restaurants, cafes or bakeries if you know you have airborne allergies.

Usually, leaving the area, getting some fresh air and taking antihistamine or an inhaler can dull the reaction but be sure to always carry your adrenaline injectors and use them at any sign of anaphylaxis.

If you are in a confined area, like an aeroplane, and have experienced airborne allergies, it is a good idea to talk to staff about what meals will be served, ask for an announcement and consider carrying a HEPA filter mask.