Casual exposure
Many people believe that the mere presence of a food can contaminate the surrounding airborne environment, making the area unsafe for the allergic child.
This section provides more details about the risks of casual exposure to foods such as fish and peanut.
Fish
With certain foods such as fish, the vapor or steam has been shown to contain allergens which can trigger asthmatic reactions and even anaphylaxis.1,2 Caution should be exercised.
Peanut
A recent U.S. study3 explored the commonly held beliefs that peanut odor and skin contact with peanut products pose a significant risk to peanut-allergic individuals. Many people believe that the mere presence of peanut products can contaminate the surrounding airborne environment, making an area unsafe for a peanut-allergic child.
Allergic reactions to foods such as peanut butter are triggered by specific food proteins. Food odor is caused by non-protein chemicals. Smelling peanut butter odor is different from inhaling airborne peanut particles (proteins) which might occur from the mass shelling of peanuts in a poorly ventilated area.
Peanut-allergic people may feel unwell if they smell peanut butter, but this is likely due to a strong (and understandable) psychological aversion. Inhaling airborne peanut particles can cause allergic reactions with symptoms such as rashes, runny nose, itchy eyes, and occasionally wheezing, but anaphylaxis is thought to be unlikely.
Some people worry that just touching small amounts of peanut butter will result in a significant or life-threatening allergic reaction. The researchers noted that a very small amount of peanut butter induced only a local reaction when touched; however, the same amount could cause anaphylaxis should it be unintentionally transferred to the mouth.
While the researchers hope that their study will allay concerns about casual exposure to peanut, they advise continued caution:
“Indeed, trace quantities of peanut can induce reactions when ingested, and intimate kissing, although perhaps considered casual contact, is also akin to ingestion.” They add: “Specifically, on the basis of this study alone, we would not recommend changing any school policies that protect children with peanut allergy.”
The researchers also stressed that they did not study the effects of having a large amount of peanut or peanut butter in the room and that further investigation would be required.
Note: An article titled "Common Beliefs About Peanut Allergy: Fact or Fiction?" further explains the difference between smelling a food odour and ingesting airborne food allergens.
- Crespo JF, Pascual C, Dominguez C, Ojeda I, Munoz FM, Estaban MM. Allergic reactions associated with airborne fish particles in IgE-mediated fish hypersensitive patients. Allergy 1995;50(3):257-61.
- Roberts G, Golder N, Lack G. Bronchial challenges with aerosolized food in asthmatic, food-allergic children. Allergy 2002;57:713-7.
- Simonte SJ, Songhui Ma, Mofidi S, Sicherer SH. Relevance of casual contact with peanut butter in children with peanut allergy. Journal of Allergy and Clinical Immunology 2003;112:180-2.
