Wednesday, August 22, 2012

Are Food Allergy Bans Even Protective?

I just love this picture.
What was this guy thinking about?
There's been wailing and gnashing of teeth this week because the National Association of School Nurses came out with a new position paper regarding food allergies. (It actually came out in June, but it seems to have just hit most of the chat boards this month.) Many food allergy advocates were disappointed because of the statement about food bans:

Maintaining a healthy environment is essential.  All environments in the school setting require special attention to protect students by limiting allergens or providing areas that are allergen safe (National School Boards Association [NBSA], 2011).   Completely banning nuts or other foods is not recommended as it is 1) not possible to control what other people bring onto the school grounds, and 2) does not provide the allergic student with an environment where he/she can safely learn to navigate a world containing nuts.  When a ban is instituted, parents feel their child will not be exposed to allergens.  A ban can create a false sense of security (“Banning allergies from school”, 2012).

There's one phrase in there that's designed to ruffle the feathers of moms of older kids: "false sense of security." That particular wording goes back to the early days of FAAN when Anne Munoz-Furlong was still running the show. There was such strong feeling about this issue that many people stopped contributing to FAAN as a result of that one statement.

Personally, I have always felt a special kindred for AMF because she also has a child with a severe milk allergy, and milk allergy definitely gives you a different perspective on the world. I don't disagree with the "false sense of security" statement.

But that's not what this blog entry is about! We could argue endlessly about peanut bans, and I have addressed them in another blog post. What I'm more interested in talking about today is whether they even do anything to protect most kids.

If you get into debating the need for peanut bans on any of the chat boards, you'll quickly learn that many people believe that  reducing the amount of peanut surrounding their child is, in and of itself, protective. You see a lot of statements like "yes, a ban is not perfect, but it reduces the amount of peanut in the school, even if some people cheat." 

If you stick around longer, you'll probably also notice that people often speak about the peanut in a phobic way. It supposedly "floats in the air" and "sticks to every surface." It's like a tiger, just waiting to jump out and attack our children. The less peanut, the safer the child. 

But does that even make sense? 

Let's go back to last month's post about thresholds. In that post, I cited research that showed that, in the research group studied, 1% of food allergic individuals reacted to 2 mg or less of peanut. Another 16-18% had a threshold that's between 2 and 65 mg. (65 mg is equivalent to 1/5 of a peanut.) 

There's another important concept to threshold: gradual vs. cliff trigger response. What does this mean? 

With a gradual trigger reaction, symptoms would build as the amount of allergen in the system builds. If a child received a micro dose of an allergen, they would have a micro response, and responses would build and remain proportional to the dose.

With a cliff trigger response, a child would go from fine (no symptoms) to reaction. 

My understanding is that the vast majority of reactions out there are the cliff trigger variety. The threshold may change based on different environmental factors (hormones, illness, exercise, etc.), but it takes a certain amount of protein to tip a child into a reaction. Up until that point, there are usually no symptoms. 

The clinical trial we're currently in depends on this being the case. We will return to the hospital in October and my son will go back through the same set of challenges he experienced in April. The success or failure of the medication (assuming he does not have placebo) is predicated on him failing at a particular dose level. Below half a peanut - nothing. Above half a peanut - start of a reaction. (More peanut would certainly escalate things, but it takes a cumulative dose of at least a half peanut to get the ball rolling for him.)  

So, if we put those two concepts together: most children require at least 1/5 of a peanut to get a reaction started, and amounts below 1/5 of a peanut generally causes no trouble.

Is all that a guarantee? Of course not. But I think you can see how thinking about reactions as a cliff response rather than a gradual trigger response can be reassuring for most families. If your child is in the category of hyper reactors, you already know it. They have had reactions (not just hives - reactions) from being at the grocery store, the park, the movie theater. If your child is in this category, they very well may require a ban to be safer at school. 

"But what about contact reactions?" you ask. Yes, kids can get localized hives from contact reactions, but anaphylactic reactions to contact or inhaled peanut are very rare. (Here's a summary from Michael C. Young writing for FARE in Canada about inhalation/contact reactions.)  That's not to say that constant contact reactions aren't a pain in the rear! Again, kids who experience constant contact reactions would probably benefit from a ban. 

For the rest of our children...not so much. Having peanut around them doesn't affect them. Very few children are able to accidentally ingest a fifth of a peanut, unless they're licking their desk surfaces. (Preschools - totally different approach. I strongly believe they should be food-free. Kids at that age clearly do lick their desks, toys and likely each other.)

The sad part of all of this is that, probably at least in part due to the phobia and overreaction of parents who did not need this level of protection, we now have a strong policy statement from the NASN. It's going to make it a LOT harder for the kids who really could benefit from a ban to get one. 

At the end of every ban debate, there's always someone who just comes right out and says it: "why shouldn't I ask for a ban if it could make my child even the tiniest bit safer?" The answer is because invasive actions like food bans have backlash. People do cheat, kids do bully, parents are crappy, organizations do come out with policy statements. Asking for more than we really need always results in backlash. If a ban doesn't even make your child safer, why in the world would you sign up for all that?