COL Glenn alerted me to a blog post where a child on a plane had a severe peanut allergy, and anaphylaxed (stopped breathing) when a passenger 4 rows away had opened a bag of peanuts. He wanted my medical opinion on this case. I find her anaphylaxis from 4 rows away by smelling peanuts dubious, but I’m not an allergist, I’m an ER doc, so I asked my allergist friend (who wished to remain nameless, but works at a top 10 nationally ranked hospital). He said this would be virtually impossible unless the peanuts were ground finely and aerosolized. Here’s the medscape article on inhalation of peanuts.
I read one study where found researchers failed to detect peanut in air filters at the level of the neck after volunteers danced on peanuts on the floor of a poorly ventilated room (Perry TT, Conover-Walker MK, Pomes A, Chapman MD, Wood RA. Distribution of peanut allergen in the environment. J Allergy Clin Immunol. 2004;113:973-976). There was also a study where people with severe peanut allergies smelled a jar of peanut butter from very close range but experienced no allergic side effects (Simonte SJ, Ma S, Mofidi S, Sicherer SH. Relevance of casual contact with peanut butter in children with peanut allergy. J Allergy Clin Immunol. 2003;112:180-182). There is still persistent belief that just smelling peanuts can cause anaphylaxis; however the medical literature does not support this, as there have only been anecdotal cases.
From my perspective, if you’ve got such a severe allergy that you anaphylax from smelling peanuts, you need an epi-pen on you at all times, and you need to immediately see an allergist for desensitization therapy, because you’re constantly at risk of death.