Comments on: Peanut Allergy vs. Peanut Sensitization

By: fleickly

fleickly — Tue, 24 Aug 2010 00:28:49 +0000

From the home page you can scroll down to reach the article. Or you can use a title/topic link on the left for food allergy topics. Contact urticaria (hives) can occur with many foods and with many other items. I have a few patients who can eat a P&J sandwich and do just fine. However, if the sandwich touch the skin (usually the cheeks next to the lips) they get hives. Some foods were not meant to be worn. Looking at the specific IgE via a blood test may help predict the chances of a reaction. Your pediatric allergist can select the appropriate test for peanut. The allergist should have a handle on what levels of peanut specific IgE have a significant risk of a reaction. If the sensitivity/allergy is outgrown the specific IgE levels decrease over time.
FEL

By: Rita

Rita — Mon, 23 Aug 2010 22:52:13 +0000

I was unable to open the link about misdiagnosing peanut allergies…but would like to read it. My 2.5 year old has never actually eaten peanuts, his only exposure would have been via breastmilk and prior to birth. At 18 months he was picked up by someone who had just eaten peanuts and developed hives. His skin prick test was positive. He did have a blood test for all major allergens several months earlier (with a different doctor than the skin prick) which was negative. Would a child who is sensitized to peanuts react with hives when their skin comes into contact with peanut proteins or is that more indicative of an allergy? I am just curious if we should try to pursue CRD at our next appointment or if I am just being overly hopeful that this may not be an issue for him…

Thanks!

By: fleickly

fleickly — Mon, 23 Aug 2010 16:55:38 +0000

Very interesting question. Sensitization means making an antibody against something. In this context, a person with a positive skin test or a positive blood test for peanut has evidence that an IgE antibody is being made.
Now for that person to be allergic, symptoms will occur with exposure. So to be allergic you have the symptoms consistent with a type I allergic reaction and evidence of having the antibody.
One of my postings reviews an article about misdiagnosing peanut allergy in 2/3 children. The thought here is that they are sensitized to other proteins and perhaps not those associated with servere allergic reactions.
Patients who ‘tolerate’ peanuts- eat them with great regularity, may have a positive allergy test to peanut. The theory is that as long as the immune system sees the peanut proteins with some frequency the features or symptoms of allergy do not occur- they are tolerant.
In a round about way to answer your question- if a peanut sensitized child eats peanuts daily, I would think that child is ‘tolerant’ to the peanut. If the exposure to peanuts is stopped or becomes very sporadic, then ‘tolerance’ may be lost and allergy can happen.
Phadia is working on an assay (see prior reports on Microarray) that may help to sort out what proteins the child is reacting to. This may be of great help.
We have seen 321 children with a positive skin test to peanut since January 1, 2009- very few of the group who only had an allergy test for peanut (no history of a reaction to peanut) went on to have an allergic reaction.
Great question- as you can see the answer is not clear-cut. We are still looking for more definitive statements from those who are doing peanut research.
Thanks for posting the question,
FEL

By: Rita

Rita — Mon, 23 Aug 2010 15:55:06 +0000

Are children who are sensitized to peanuts more likely to develop a peanut allergy with continued exposure?