Friday, May 15, 2009

Food Allergy Awareness Week: Technical Stuff In Three Parts

Part One: Prior/Indirect Exposure

A couple of people have asked questions about Harper's level of exposure to peanut products before she had that first reaction. Trust me when I say we were not a peanut free house - not by any stretch of the imagination. Matt at peanut butter and jelly several times a week. We at candy with peanut butter in it, granola bars with nuts in them, peanut butter toast, and at least once a week gave the dog peanut butter inside a rubber chew toy. I know she'd had bites of granola bars which may have had peanuts in them and she may have been exposed through plain M&Ms. In fact we know she'd had at least one exposure before the peanut jar incident, because you can't have an allergic reaction to something without first being sensitized to it. And I know I ate peanuts and peanut butter while I was nursing and while I was pregnant.

In fact, Harper had terrible eczema during the first year of her life - there was one spot on her cheek that was always very raw looking. Our pediatrician sort of dismissed it, kids have eczema and it isn't necessarily a big deal. It cleared up instantly when I stopped nursing her. So I am pretty sure that eczema was a reaction to peanut protein she was getting through my breast milk. I wished I had tried harder to find the cause of it while I was still nursing her. I don't think I CAUSED Harper's allergy with this exposure, but it may have been exacerbated. The allergist told me to strictly avoid peanuts if I got pregnant again and I did not have a single peanut (to my knowledge) while I was carrying Michael or when he was drinking my breast milk.

At the very least I would caution other parents to watch children carefully for signs of a reaction the first several times they eat a highly allergenic food like peanut butter - even if you're sure they've already been exposed to peanut products around your home.

Also - people can develop allergies to anything at any point in their lives. I don't think that means we all need to walk around with epi pens, but just because a child does not have an allergic history with a food doesn't mean they can never become allergic.

Part Two: Testing/Outgrowing a Peanut Allergy

There are different theories out there about how and when children, even those with known allergies, ought to be tested. There are two tests (to my knowledge) for food allergies; one is a blood test and one is a skin test. Harper has had repeated blood tests to check her peanut allergy levels and has had blood and skin tests to rule out other allergies (tree nuts, oranges, sunflower seeds - those are the ones I can think of). Our allergist told us that a negative blood test can leave you 75% certain a child is not allergic and you only get 100% when you pair it with a negative skin test. We have never skin-tested Harper for peanuts as we know from her blood tests and history that she is allergic.

We have Harper tested about once a year. In terms of her peanut allergy we retest her to see how the numbers are trending. When we go in for her peanut allergy testing we will add other tests if there are foods we are concerned about.

Discouragingly, Harper's peanut allergy numbers have skyrocketed since she was first diagnosed. I have read that numbers tend to peak around age three (I can offer no explanation for this, but it is a silly thing that I hold on to) - this year we'll test her again before school begins so maybe we'll find her numbers have stabilized or even dropped some.

Only about 20% of children with peanut allergies outgrow them, and those who do tend to have low numbers to begin them and outgrow them at a young age, typically by about five years old. Peanut (and I believe tree nut as well) allergies are more likely to stick around than some others that are common in young children, like dairy and egg allergies.

A food challenge, done under close medical supervision, is the ultimate way to determine whether an allergy has been outgrown. Harper's numbers are nowhere near low enough for us to consider such a thing.

I get nervous when I hear people talk about "mild" peanut allergies. Everything I have read and been told states that there is no such thing. Peanut allergies are volatile, a past reaction is not necessarily an indicator of what a future reaction will look like, and even people with low numbers can have severe reactions to a tiny amount of peanut protein. We have always treated Harper's allergy as "severe" even when her numbers were low.

Part Three: Medications

Swistle asked specifically about EpiPens and how they work, plus some other questions about what happens when an allergic reaction occurs. Here is my very non-scientific, non-medical, as well as I understand it explanation...

An EpiPen is basically loaded with adrenalene, which can work to reverse the effects of an anaphylactic reaction. Prompt use of an EpiPen during an allergic reaction can temporarily relieve swelling and hives (which can restrict the airway) and counteract a sudden drop in blood pressure, all of which may occur in the case of a severe allergic reaction. Often EpiPens are used in conjunction with Benadryl, and it is my understanding that Benadryl can help combat a minor reaction and provide comfort for things like itchy hives. Benadryl is not going to be life-saving in the case of a severe reaction.

Depending on the severity of the reaction, the medication in an EpiPen can start to wear off after ten to fifteen minutes. With very few exceptions we always carry at least two EpiPens (We are NEVER without one). Most of the time we also carry Benadryl and a rescue inhaler (which is for asthma difficulty and would not help in an allergic emergency). It is helpful for people at risk for anaphylactic shock to know whether their local emergency response teams carry epinepherine and what their response time is likely to be. People in areas where it would be difficult for the paramedics to get to them should have more than two EpiPens available.

In a severe reaction medication would be needed at the hospital and perhaps for several days after - I have heard of people having severe reactions and then having trouble with hives for days afterward.

There is also a risk of something called a biphasic reaction, in which a second reaction comes on hours after the first and often stronger. If we ever went to the emergency room for an allergic reaction and were discharged less than six hours after our arrival, I would wait in a waiting area or lobby until that amount of time had gone by, to be sure we weren't away from medical assistance if a biphasic reaction occured.

One thing our allergist really drilled into my head was the fact that it is always better to use the EpiPen than wait and see. She told us that is the number one mistake patients and care-givers make - waiting too long to use it or not using it at all. It is possible to reach a point in an allergic reaction when an EpiPen will no longer help. That's why, at school for example, Harper's EpiPens are supposed to go with her (carried by a teacher) whenever she leaves the classroom. It's also why we would not agree to a situation where her EpiPen had to be locked in the school office, as many other meds are. In an allergic emergency there really may not be time to run and retreive the EpiPen.


In many ways I feel like my posts this week have been a poor attempt to convey all we've learned about dealing with food allergies - it is overwhelming to attempt to pair the information swimming around my brain down to any reasonable length! For people who are really interested in learning more, and would perhaps like a more proper technical explanation of all of this, I recommend The Peanut Allergy Answer Book.

On a final note - we bought a used minivan today! Yea!

The first thing we did was take it to a car wash to be detailed (really, really thoroughly cleaned) because I want to make sure there is no peanut residue in the van when I put the children in it. I'm telling you, this allergy thing never ends.


Swistle said...

I'm finding this whole thing very interesting.

Anne said...

Like most things medical, I'm fascinated by this. I can completely identify with your concerns and all the precautions you take to protect your child. I have Archie and he's had his extreme health challenges so I get the thinking ahead thing, the way a parent plans for the worst and does all s/he can to eliminate pitfalls and problems.

One thing I've encountered is friends and family members who think I'm batsh*t crazy to do what I do in regards to protecting Archie's health. Even when he was undergoing chemo and we refused to let people into our house to visit with him or the twins, who were newly born then, we got flak for our decision. I hated that. People's disregard for our wishes, the way they totally dismissed our worries, really frustrated me. In other words, they abide by our wishes, but they talked about us in unkind ways.

I'm wondering if you get that sort of thing, too, in regards to Harpers' allergy? I mean, do the teachers at her school cooperate? Do they get it? I'd worry incessantly about that.

Jane Anne said...

Hi, I found your blog through my Google Alert on "peanut allergy". I have enjoyed reading the last several posts. I think you are doing a fantastic job protecting your daughter. My son is also allergic to peanuts. I blogged about his allergy all week, too, for Food Allergy Awareness Week. Feel free to stop by: Gravity of Motion