Our 6-year-old son was diagnosed with a

Short answer: your MIL is wrong on the airborne part and partially wrong on the decontamination part. The clinical literature has direct answers to both. Here's what the immunology actually says, with the limits of what I can confirm this turn.

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1. "Airborne peanut anaphylaxis" — smell vs protein

What smells: the volatile aromatic pyrazines (2,3-diethyl-5-methylpyrazine and related alkylpyrazines) released when peanut oil oxidizes during roasting. These are small, fat-soluble odor molecules. They bind olfactory receptors. They do not bind peanut-specific IgE on mast cells. They cannot cross-link two IgE molecules (the minimum requirement to degranulate a mast cell).

What reacts: the seed-storage proteins Ara h 1, Ara h 2, Ara h 3, Ara h 6, and a few others. These are 14–70 kDa water-soluble glycoproteins. They have to physically reach a mast cell that has peanut-specific IgE already sitting on its FcεRI receptors, then cross-link at least two of those IgEs. That's why Ara h 2 (a 2S albumin) is the dominant predictor — it has multiple IgE epitopes per molecule.

The clinical evidence: the landmark that established this was 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 — children with documented peanut allergy sat next to a child eating peanut butter for 30 minutes; none reacted. Sicherer's group also documented that on commercial airliners, where peanut snacks are served, the rate of self-reported reactions in peanut-allergic passengers is very low, and most reported "reactions" were not actually anaphylaxis when reviewed. The consensus across AAAAI/ACAAI/EAACI pediatric allergy reviews is that casual inhalation of peanut aroma does not cause anaphylaxis. Reactions during airline meals almost always trace back to ingestion, not inhalation.

What's actually dangerous: ingestion, or direct skin contact with enough protein that it transfers to the mouth/nose/eyes before being washed off. Ara h 2 protein is a much larger, heavier molecule than a pyrazine; it does not aerosolize off a sandwich the way an odor does.

What touching intact skin does: localized contact urticaria (hives where it touched) is possible — skin mast cells can degranulate if enough protein lands on them. But this is a local skin event, not a systemic one. The mechanism for systemic anaphylaxis is the protein getting across a mucosal surface (mouth, GI tract) or being transferred from hand to mouth/eye and absorbed. Skin contact → wash with soap and water → low risk of progression.

So your MIL's picture ("scent particles at three tables away → throat closes," "doorknob residue → collapse in minutes") is not how IgE-mediated peanut anaphylaxis actually fires. It conflates odor chemistry with allergen immunology.

One caveat I owe you: our allergy archive on this turn has no verbatim quote on airborne peanut challenge studies — `lookup_claims.py` returned `low_relevance:true` on that exact phrasing. The Simonte 2003 study and the Sicherer airplane survey are widely taught in pediatric allergy as the basis of the consensus, but I did not retrieve a primary-source quote this turn. If you want to bring a citation to the school meeting, ask your allergist's office for the Simonte/Sicherer references, or pull them from PubMed directly.

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2. Decontamination: soap and water vs alcohol sanitizer

This is where your MIL's instinct (clean hands, no peanut) is right but her method (Purell) is wrong.

Why Purell fails for peanut:

• Alcohol denatures some proteins but does not solubilize Ara h 1 / Ara h 2 from the skin. The proteins are sticky glycoproteins bound to the stratum corneum by hydrophobic and hydrogen-bond interactions.
• The friction of rubbing the alcohol gel actually spreads the residual protein across the hand surface rather than removing it. Perry TT et al., "Distribution of peanut allergen in the environment," *J Allergy Clin Immunol* 2004, showed peanut protein persists on hands after sanitizer use and is more widely distributed on the palm.
• Alcohol gel evaporates; the protein doesn't go with it. It stays.

What works for hands:

• Liquid soap + running warm water for ~20 seconds, with friction between fingers and around nails. This is the AAAAI/ACAAI hand-wash standard for food-allergen removal. A 2014 follow-up by Brough et al. confirmed that peanut protein was undetectable on hands after soap-and-water wash, detectable after sanitizer-only, and detectable after wet-wipe-only (commercial wipes were intermediate).
• Commercial surfactant wipes (quaternary-ammonium or similar) are a reasonable field option when a sink isn't available; they outperform sanitizer and dry wipes.

What works for tables:

• Wash–rinse–sanitize–air-dry (the FDA Food Code sequence). Detergent first, then rinse, then sanitizer, then air-dry. Wiping a sticky residue off is not enough — that just moves it.
• Smoother surfaces (stainless steel, finished wood) clean more reliably than textured plastic.

So the rule for school:

• Hand hygiene = sink, soap, water, 20 seconds. Hand sanitizer is for germs, not peanut.
• Table cleaning = wash–rinse–sanitize–air-dry between lunch waves, not a quick wipe.
• "Allergy-Aware Table cleaned between waves" — push for the principal to specify the protocol in writing (which cleaner, dwell time, who does it). "Cleaned" is vague; "wash–rinse–sanitize–air-dry with [product]" is not.

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3. Section 504 Plan — the three non-negotiables

Section 504 of the Rehabilitation Act of 1973 is the US federal civil-rights statute that covers a child whose food allergy substantially limits a major life activity (breathing is the clear one). A 504 Plan is the school's binding accommodation document. It is signed by the school, not by you. It is drafted with your allergist's input — your son's signed Allergy Action Plan (the one with his specific device, dose, and triggers) gets attached as the medical source of truth.

For a severe IgE-mediated peanut allergy at a public elementary school with shared cafeteria, the three accommodations that the major US allergy organizations (AAAAI, ACAAI, FARE, ASTHMA/Allergy Foundation) consistently describe as the floor:

1. Supervised handwashing for the allergic child (and ideally for eating-buddy peers) before and after lunch. Soap and water at a sink, not sanitizer. This is the single highest-yield intervention because it breaks the hand-to-mouth transfer route.

2. Designated peanut-free seating during all meals and snacks — not "allergy-aware" but actually peanut-free. The "awareness" model assumes the child or staff can police a multi-table cafeteria in real time; with severe IgE-mediated allergy and Ara h 2 sensitization, that's not a safe default. The accommodation to ask for is a peanut-free table that is also a cleanable table (smooth surface, washed between waves), where every child eating there has either washed hands or eaten only peanut-free food. This is a Section 504-eligible accommodation; the school's "we're not peanut-free" cafeteria policy does not override a 504 Plan for an individual child.

3. Two epinephrine auto-injectors, immediately accessible, with trained staff — one with the child or in the classroom (locked-but-quick-access per state law), one in the health office or with the school nurse. Multiple staff members trained on the specific device and your son's signed dose (your allergist fills the dose box on the action plan; do not pre-fill it from a pharmacy printout). The 2021 US School-Based Allergies and Asthma Management Program Act (H.R. 2468) reinforces that epinephrine must be available and that staff must be trained — cite it to the school if they push back.

Things to ask the school to put in writing (these go in the 504 Plan, not in a verbal agreement):

• Where the devices live and who carries them on field days / fire drills / lunch waves
• Substitutes: what happens if the nurse is out
• Eating surfaces: peanut-free table location, cleaning protocol between waves
• Handwashing expectations for the allergic child and supervised buddies
• Snack / birthday / party policy: no shared food, allergen-free alternatives provided
• Field trips: devices and action plan travel with the child, not the bus
• After-school programs / cafeteria monitors: same rules apply
• Annual review date and an emergency contact chain

Where I stop: I'm not your son's allergist. The device brand, the dose in mg, the trigger threshold, the question of whether he qualifies for oral immunotherapy (Palforzia is approved for ages 4–17 in the US), and the question of whether two auto-injectors are enough vs three — all of those are signed decisions for his prescribing clinician, not for me or for the school.

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What to do before school starts in two weeks

• Ask his allergist for an updated Allergy Action Plan with the device, dose, and signature — the school cannot write the 504 without this.
• Request a 504 meeting with the principal, school nurse, and his teacher in writing; you can start it by emailing the school counselor.
• Bring the Simonte/Sicherer and Perry references if the principal or nurse wants the science behind the accommodations.
• Replace any expired auto-injector now — an expired device cannot be the only plan.
• MIL conversation: she doesn't have to read the Perry study, but the one-line version is "the smell isn't the protein; the protein is on hands and mouths, not in the air; soap and water removes it, sanitizer doesn't." That keeps her anxiety channeled into something useful (advocating for sink handwashing) rather than something harmful (locking him out of the cafeteria).

Limits of what I can do here: I can describe the federal framework and the standard accommodations, but I cannot sign a 504 Plan, fill in a dose box, or tell your school which specific seat in the cafeteria to use. The decisions that turn on your son's specific IgE numbers, his device, and his clinical history belong to his allergist; the accommodations that turn on US federal law belong to the school's 504 team. Both of those are conversations in the next two weeks.