Airborne exposure to peanuts did not produce severe reactions

Many people suffering from an allergy to peanuts are afraid to having a reaction to peanuts through the air. But a new study provides reassuring news.

Caroline Nilsson
Caroline Nilsson. Photo: Photo group Södersjukhuset.

Text: Ola Danielsson, first published in Swedish in the magazine Medicinsk Vetenskap no 2/2021. 

In the worst case scenario, people suffering from an allergy to peanuts can have life-threatening symptoms. It is more unclear whether airborne exposure, e.g., being in the vicinity of peanuts, can also pose a risk to people suffering from an allergy to peanuts. 

"Many allergy sufferers are concerned about airborne reactions," says Caroline Nilsson, a researcher at the Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet. 

She has now tried to get to the bottom of the issue of airborne peanut allergy through a series of trials in which 84 children with peanut allergy participated. The children had to sit in front of bowl containing 300 grams of peanuts at a distance of half a metre. The bowl was subsequently removed and the child was observed for another hour. 

"It went perfectly fine. Two of the children had mild symptoms, itching of the eyes, but no one else had any reaction," says Caroline Nilsson. 

Other scientists have also tried to induce allergic airborne reactions from peanuts, but so far no one has succeeded. There is also no described case of severe reaction or death from peanuts via the air.

Peanuts. Photo:

Caroline Nilsson, however, takes the experiences of airborne reactions seriously. 

"If you have experienced a severe allergic reaction from ingesting peanuts through your food and later sense the distinct smell of peanuts, your body may have a reaction to this. The immune system can be activated and play a trick on you. However, this is not an allergic reaction and there are no severe symptoms that occur in that way," says Caroline Nilsson. 

The substances that are perceived as the smell of peanuts are not the same substances that can trigger an allergic reaction. 

"The odour molecules do not consist of proteins. They are simply the proteins that your are allergic to," says Caroline Nilsson. 

However, the researchers were able to detect traces of peanut protein in the air using sensitive measurement methods, primarily at a distance of less than one centimetre around the peanuts. 

"The amount of protein in the air is so small that it is unlikely to cause moderate or severe allergic reactions, something we have not seen in any of the participants in the study either.”   

Reference: Clinical & Experimental Allergy, April 2021

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