Using the Phadia Microarray for Peanut Allergy-Wishing it was readily available.

Yesterday (March 28, 2010), I saw a young lady of 4 years in our allergy clinic at the Riley Outpatient Center for concerns about peanut allergy. She had one of those infrequently seen presentations, at least infrequent in my pediatric peanut population. Her symptoms were most consistent with the oral allergy syndrome. The symptoms were immediate with excessive salivation that lasted for about 15 minutes. She was vague, as many 4 years tend to be, about other oral symptoms such as an itchy mouth or hoarseness. She has had this happen about 5 times over the past two years. The first episode was sometime during her second year.

Now she also has nasal allergy that is very well controlled on an antihistamine. She ate almonds with impunity, but had one experience with cashew that caused the same symptoms.

We tested her for cashew and peanut- they were positive. We also tested her for birch and alder tree pollen, hazelnut, celery, apple, peach, and carrot. Birch and hazelnut (food) were also positive. I felt very sure that she had peanut- induced oral allergy syndrome. She was given injectable epinephrine, information regarding the Food Allergy and Anaphylaxis Network, and information on medical alert bracelets.

I only wished that I could have ordered a few additional blood tests to help provide some guidance regarding the seriousness of her peanut reaction.

We are currently working with a large group of children who have been seen at Riley Hospital for Children with peanut positive skin prick tests. This group of 76 children (from the 350 we have seen over the past year who have had a positive skin test to peanut) had wide variety of clinical presentations for their peanut allergy. Phadia has performed their microarray assay on these children. Now I am eagerly working on the information looking for associations, frequencies, odds ratios, and predictive values. This project and what I read in the literature, indicates that reactions to specific peanut proteins may help predict who will have a serious reaction to peanut. What we see is that the skin test for peanut and even the blood test for peanut tend to be rather crude tests and may measure antibody responses to a wide variety of proteins in peanut, not all of which are important in causing serious reactions. Positive peanut test results may be due to proteins in peanut that are shared with other members of the plant kingdom. So a child may have a positive screening test, by skin prick or by blood, but not show reactivity to the proteins associated with serious reactions and may show possible cross-reactivity to birch or alder tree pollen or the foods celery, carrot, apple, peach, or hazelnut.

My guess is that this young lady has the oral allergy syndrome due to peanut. I await her ImmunoCap specific IgE to peanut- her value may be low enough, below the critical cut-off point, to allow her to undergo a safe peanut challenge. However, I would have relished the opportunity to evaluate her responses via the Phadia microarray. This may help with my diagnosis and guidance. Knowing the specifics of her response may help with the family’s fear of a more serious peanut reaction, it may help with her socialization at school, and it may obviate the need for having injectable epinephrine.

Just another day in clinic!

FEL

March 29, 2011 · fleickly · 6 Comments
Tags: , ,  · Posted in: Allergy Testing, Food Allergies, Peanut Allergy, Phadia Allergy Tests

6 Responses

  1. Rita - November 5, 2011

    What are your thoughts on Phadia’s uKnow peanut test? Is it a test that you are using?

    Thanks!

  2. fleickly - November 7, 2011

    I am not sure what the ‘marketed’ name for the peanut test is ( I will connect with my contact Mr. J. Jones regarding the name). What and many others who have interests in peanut allergy are the components- so this would be component testing. The peanut proteins that elicit responses of concern may include Ara h1, h2, and h3. Phadia has also helped with Ara h8 and h9.
    Can I inquire regarding your interest? Parent, patient, researcher, or other intersted party?
    Thanks for looking at the site,
    FEL

  3. Rita - November 7, 2011

    My 4 year old has a peanut allergy and I am wondering if this test is worthwhile. We have never seen a reaction, other than hives at 18 months when he was picked up by someone who had been eating peanuts. I figure this test will either confirm what we have been told to assume (anaphylaxis) or, perhaps, ease my mind a bit. We are actually planning to schedule an appointment with you.

  4. Rita - November 18, 2011

    We’ve scheduled an appointment and look forward to meeting you on December 7!

  5. stacy - June 3, 2012

    I am wondering if this would even be worth it or not in our situation. My daughter almost died from peanut induced anaphylaxis. She ended up on an oscillator for 2 days followed by a ventilator for an additional 5 days. Her Co2 levels reached the 180’s and almost had to be put on ECMO because of this reaction. That was in October of 2011. Just this month. A dog licked her on the arm and her arm turned bright red and developed small blisters and within 3-4 minutes her throat became itchy…fortunatley the benedryl worked for that occasion. However, in the anaphylaxis episode, the epi pen worked for 10 minutes to get her to the hospital then after that everything went down hill and she was no longer responding to the epi. Total stabilization time was approx. 4 hours.

  6. fleickly - June 13, 2012

    What a terrible ordeal to go through. Her story is one of the most severe I have heard.
    If your question was related to the component testing there are a couple of ways of looking at the options. First- it will not change your behavior- she still will need to avoid peanuts. Second, having the component results early would establish a point from which she may stay at (80% may not outgrow their peanut allergy) or a point from which with subsequent testing there may be a decline in the number. The test is about $350 and you would pay up front. Blood is sent to the company (Now Thermo). Your third party coverage may or may not compensate you for the Uknow test.
    Thanks for looking at the site and for sharing your experience,
    FEL