skin prick tests

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Can any one explain or give me a couple of 'links' to help me understand the debate against skin prick tests?

thanks in advance , sarah

On Nov 15, 2005

I don't have any links that will help, but we don't do them any more after talking with M's Dr. M had a very violent reaction after his last skin test (was probably the third yearly one he'd had). Doc explained that since allergies worsen upon exposure to the allergen, it was an unnecessary risk to continue exposing him to peanut oil just to test him when the blood test is available. He said any more testing could cause an anaphylactic reaction and he wasn't willing to push it any more. He will only do the annual testing by blood work.

Any links you do find, I'd be interested in reading. Thanks!!

------------------ Little Man's Momma a*k*a Kendra

On Nov 15, 2005

A recent debate against skin prick tests here? A medical debate against skin prick tests? Just personal experience posted here that would show you why some of us choose not to skin prick test?

I need you to be clearer so I can help you. [img]http://uumor.pair.com/nutalle2/peanutallergy/wink.gif[/img]

Best wishes! [img]http://uumor.pair.com/nutalle2/peanutallergy/smile.gif[/img]

------------------ "That was Polanski. Nicholson got his nose cut."

On Nov 16, 2005

I have always been aware that there is some sort of conflict over skin prick tests , I get the impression that Canada and America stick to blood tests for allergies. Rather than a combination of skin and blood tests. (My sons clinic do both, taking allergy /atopic history in to account.)

I wanted to know if thats an opinon that an allergiest has for all children, or is that conclusion or judgment of risk , for each individual case?

I know that skin prick tests have been around since the 60's, and are pretty good for producing clear results for peanut allergy.

In my personal experience ,my sons clinic only skin prick test for already suspected allergies.

So, what are the risks? Can skin prick tests make a allergy worse?

Are blood tests alone a reliable indicator of allergy level?

Could you have a food challenge based just on the results of your blood test?

What are the reasons that a parent would have to consider if they choose to refuse skin prick tests?

What has your allergist /medical expert told you?

sarah

On Nov 16, 2005

williamsmummy, thank-you for clarifying. [img]http://uumor.pair.com/nutalle2/peanutallergy/smile.gif[/img]

Now to answer would be a whole other story. [img]http://uumor.pair.com/nutalle2/peanutallergy/wink.gif[/img]

Best wishes! [img]http://uumor.pair.com/nutalle2/peanutallergy/smile.gif[/img]

------------------ "That was Polanski. Nicholson got his nose cut."

On Nov 16, 2005

Okay, let's see if I can answer some of these questions, but with the understanding that, not that I don't believe in allergy testing, but my guy has only had skin prick testing once and I'm not planning on any further allergy testing unless I think he has developed a new food allergy.

Quote:

Originally posted by williamsmummy: [b]I have always been aware that there is some sort of conflict over skin prick tests , I get the impression that Canada and America stick to blood tests for allergies. Rather than a combination of skin and blood tests.

Okay, the allergist that my son saw is an associate of Dr. Peter Vadas who is very highly regarded in Toronto (or Canada) re food allergies. So, because he works out of the same office, I'm assuming that he must be pretty darn good himself.

At any rate, no - skin prick testing is done here as well and I think really it's done first in Canada, unless you know enough to ask for a blood test.

I was skin prick tested (but never for food allergies) yes, in the 1960's and again the 1980's.

If I did think that my son had developed a new food allergy (or if my daughter had developed one at all), I would ask for a blood test this time, only because when we did the skin prick testing I found it so confusing I had to post about it here to get it all figured out, had mostly ALL false positives due to ezcema on my son's back, and I do think the RAST test is more reliable from what I have read here only.

Am thinking that the Anaphylaxis Campaign may be able to answer you *properly*.

I wanted to know if thats an opinon that an allergiest has for all children, or is that conclusion or judgment of risk , for each individual case?

Okay, the only reason we saw an allergist for skin prick testing was I wanted to find out if my daughter was PA or not before she entered school. Again, I came out of the office rather confused. I mean, she had never been exposed to peanut products, so was the skin prick test her *first* exposure? Did it mean nothing?

As far as my son, I already knew then that he was PA (two anaphylactic reactions, three reactions in all by then) and what I asked was that they not put the peanut serum on his back. Turns out they could not do that, but what they could do was NOT prick the skin. He ended up with a huge wheal regardless thereby confirming, for the allergist, that my guy is PA.

I know that skin prick tests have been around since the 60's, and are pretty good for producing clear results for peanut allergy.

If it's only PA specific I'm not sure, and I would have to look at the old threads here when I had the testing done, but some of the things that both children tested positive for were quite odd (trout was one of them I believe) and they are not allergic. Jesse would not have the testing done on his upper arm and ended up having it done on his back where he had, at that time, ezcema. So, that's why I would have blood work done if ever again.

In my personal experience ,my sons clinic only skin prick test for already suspected allergies.

I can't remember everything the kids were tested for. I just know that all the serums were in one tube thing-y. I do know that the allergist did know that I was concerned about PA, for my daughter. I remember him doing something else with Em, rubbing either pb on her or something peanut-y separate from the skin prick test and that's why, despite my questions about "first exposure", he was able to tell me that she was non-PA.

So, what are the risks?

When I knew that they were going to put peanut serum on my guy who I already knew was PA, I asked if they had Benadryl and an EpiPen handy, which they did. So a risk of anaphylaxis perhaps or at least some type of reaction that you would not have if it was done blood wise.

Can skin prick tests make a allergy worse?

I have no idea, but logically thinking, I wouldn't think so. It is an *exposure* and perhaps it might if you got them done an unusually strange number of times, but I can't think why they would.

Not speaking about food allergies, but I certainly don't believe the skin prick testing I had for environmental allergies made my environmental's any worse.

Oh, the allergist that I saw at the time (both in the 1960's and 1980's - same guy), he was very highly regarded as an allergist here in Toronto, but he never said anything to me about RAST testing. Perhaps because there was no concern when the environmental allergies showed up so easily with a skin prick (mine were not false) and I was not concerned about a food allergy.

In fact, aside from the fact that we're "back home" and I can see the associate of Dr. Vadas again or perhaps even Dr. Vadas himself, if I didn't think my allergist was probably long retired (and perhaps dead and buried), I would ask for a referral to him. The only thing I didn't care for about him was that he felt the only way to control environmental allergies was through allergy shots. I don't.

Are blood tests alone a reliable indicator of allergy level?

I have no idea. Actually, what is an allergy level? The number people are given when they have a RAST test done? The numbers don't mean anything to me personally because of my guy's history and my knowing that he will not be outgrowing his allergy.

Could you have a food challenge based just on the results of your blood test?

Darnit, I just read something last night about food challenges and can't remember what it said. I'll have to check it and see if it mentioned anything about your allergy tests (skin prick or RAST) and if they figure into whether or not you're considered "eligible" for an oral challenge. Wait, there was something, yes. I'll be back with that information. Only because I knew from reading that and I believe something about outgrowing the allergy, that my guy would never be eligible for an oral challenge or be outgrowing his allergy. This was information in an Anaphylaxis Canada newsletter.

What are the reasons that a parent would have to consider if they choose to refuse skin prick tests?

The first time or subsequently? I won't have skin prick tests done again on either of my children only because my first experience with skin prick tests on both of them was so horrid and unreliable. I will pay for the blood tests instead.

That's the other thing I'm thinking, Sarah. In Canada, skin prick testing is covered. You don't have to pay for it. So, a lot of people opt for that first because it is covered, often probably does provide the results one needs (i.e., it did show Jess was PA - DUH!) and then only for your own personal reasons or for more clarity would one choose to fork out at least $20.00 per allergen to be tested. In Canada at least. KWIM? You do raise an interesting question though - how many have had skin prick tests only, blood tests only, or both? Just gotta ask that one now. [img]http://uumor.pair.com/nutalle2/peanutallergy/biggrin.gif[/img]

What has your allergist /medical expert told you?

I do not have an allergist for my kids and quite frankly, I don't feel as though I do need one, right now. If a new FA develops, then yes, I'll get a referral. Obviously, when I wanted to find out if my daughter was PA or not, my family doctor referred me to an allergist that did skin prick testing. Is there anything else that you wanted to know if the allergist/medical expert had told me/us specifically?

sarah

[/b]

I'm sorry that all came out in bold, I'm far too blah to-day to cut and paste. Hope it helped in some way and I'm going to go and re-look that newsletter, with regard to oral challenges.

Best wishes! [img]http://uumor.pair.com/nutalle2/peanutallergy/smile.gif[/img]

------------------ "That was Polanski. Nicholson got his nose cut."

On Nov 16, 2005

Quote:

Originally posted by williamsmummy: [b] So, what are the risks? Can skin prick tests make a allergy worse?

Are blood tests alone a reliable indicator of allergy level?

Could you have a food challenge based just on the results of your blood test?

What are the reasons that a parent would have to consider if they choose to refuse skin prick tests?

What has your allergist /medical expert told you?

sarah

[/b]

I have heard (writings?) that a SPT COULD lead to a reaction IN OFFICE. It touching the skin WITH the allergen ( a big ole lego block, kinda thing...)

There IS a chance.

No chance via RAST.. just drawing blood. Working under microscope, kwim?

There are false positives or negatives (or both) via ANY testing. NOT 100% foolproof.

Neither test should be used alone. Getting both done, if BOTH are negative, then an oral challenge COULD be the next step, kwim?

Does that help? Want more?

Did I get everything? We've had them both done for Caitlin...

Jason

------------------ [b]* Obsessed * [/b]

On Nov 16, 2005

Okay, this was in an Anaphylaxis Canada newsletter from this past Spring. The question posed was whether or not a child should have an oral challenge and what an oral challenge involved.

Snippets of the answer, which *might* be helpful to your discussion, not clear:-

"Some studies of children with peanut allergies have shown that those who have smaller reactions to skin tests, fewer associated allergic disorders (such as asthma), and no recent reactions to peanuts are more likely to outgrow their allergies than other children. Several studies of children with larger allergic wheals (the hives that come from skin testing) suggest that they are not likely to outgrow their allergy and therefore should not be given an oral challenge."

I've always just known that Jesse would not outgrow his allergy, but it was the part about the size of the wheal (his was very large, and remember the skin was not pricked), that was important for me to read in this specific article.

Best wishes! [img]http://uumor.pair.com/nutalle2/peanutallergy/smile.gif[/img]

------------------ "That was Polanski. Nicholson got his nose cut."

On Nov 16, 2005

When we first saw the immunologist with our son, we didnt even consider that SPT could count as an unwanted exposure. William was young and were still finding day to day life coping with his skin/allergies etc difficult.

We have had both blood and SPT over the years, with gaps of one year of two. (I cant remember isnt that terrible !! he is only 9, MB wouldnt forget something like that would she?!!! ) As he had low wheal size for egg ,we have had the cooked egg challenges( failed the raw), when he was 7. Next year when he is 10 and as his last SPT showed a low reaction to raw egg , we are going for another challenge.

On the whole we have had more SPT I think than most. As we had discovered new allergies on the way, and have had 'bigger' reactions to what was a previously mild allergy. I wanted it confirmed as a allergy that we knew about.

When william goes for his next food challenge, i am going to bring some more food to SPT for in the hope I can widen his diet in any way. I am also going to bring in the new foods he has become allergic to this year.

I have only realised that some people refuse to have their children tested as its an exposure, and just wanted to know more.

i had a friend who had a really big reaction to her SPT, and the wheal run right up her arm and she got some other symptoms, which scared her , and she is never going for them ever again.

So thats what got me thinking again about the whole safety of the tests and if its something I should consider to avoid in the future if williams allergy ridden body changes further.

sarah

On Nov 16, 2005

I just got off the phone with our pediatrician. I have had it with the allergist we went to recently, and talked to the pediatrician to get his view on it, since the allergist just tests, but doesn't talk or answer questions (NOT going back to this guy). Anyway, the pediatrician just told me that they don't even do the skin tests in Europe for FA. He says they aren't reliable for FA, but are very good for environmental allergies. I really like our pediatrician, but he is not an allergist, so I'm not sure of his level of expertise in this matter.

The reason I felt I needed to talk to the pediatrician is that DS just skin tested positive for a bunch of foods he has been eating for years. Never a reaction. Not even a teensy one, or anything that could be questionable, from any of these foods. Among them: shrimp (one of his favorites, eats just about weekly), lobster, salmon, and tree nuts (which he had a negative RAST test to just before the positive skin test, and he has eaten them by the handful). The pediatrician says to keep feeding him what I have been (the peanut RAST tested positive, he didn't get a skin test, we will definitely continue to avoid--no issue about that). He said that the test is not accurate, go by history. Which is pretty much what I wanted to hear, but now I am nervous about giving him any of those foods. I'm not sure whether I am comfortable giving those foods to him now (just makes me nervous), but on the other hand, I immediately questioned the results when I saw that these were foods he has eaten regularly (except salmon--he has tasted it but doesn't like it). I know we all have our own comfort levels, but would any of you mind giving your opinion on the conflicting info I've gotten, and what you would feel comfortable feeding your child?

On Nov 16, 2005

Now see, Jimmy's Mom, mu doctor said the exact opposite. That RAST tests test for IG-E and food allergies are mostly an IGA response, so it's not as accurate.

I'm beginning to think that no one really knows anything about how these allergies work and they just come up with their own theories as they go along. [img]http://uumor.pair.com/nutalle2/peanutallergy/frown.gif[/img]

On Nov 16, 2005

Jimmy's Mom, I would have to do a long hard search of the board to find the threads I started after I had both of my children skin prick tested. I mean, my PA guy came back with a rather odd list of things, none of which he is allergic to. My daughter even came back allergic to a couple of things as far as I can remember and she's not allergic to any foods. It was all too confusing to me.

Now, with my guy, I finally got it sorted, through posting here, that he got the false positives because he did have ezcema on his back (where the testing was done) when he had the testing. The only true positive he had, which I knew he had anyway, was PA.

Needless to say, that's why I came to the conclusion that if either of them needed any testing re FA's down the line, it would be blood work rather than SPT.

Best wishes! [img]http://uumor.pair.com/nutalle2/peanutallergy/smile.gif[/img]

------------------ "That was Polanski. Nicholson got his nose cut."

On Nov 17, 2005

opps

[This message has been edited by kkeene (edited November 17, 2005).]

On Nov 17, 2005

[url="http://www.childrensmemorial.org/depts/allergy/foodAllergies.asp"]http://www.childrensmemorial.org/depts/allergy/foodAllergies.asp[/url]

I found this interesting

& wish we could go to this hospital

On Nov 17, 2005

Jimmy's mom - About 6 months ago, I had my son (he was 6 at the time) tested for some possible new allergies. He was tested to soy, peas, green beans, almonds, pecans, cashews and walnuts. He tested positive to all except walnuts. This was very surprising since I only suspected the soy allergy and didn't really think he was allergic to any of the others. He had eaten some of these foods in the past with no apparent problems. I didn't really know what to do with the information. However, once I knew there was a possible problem, I started thinking more about his history and asking him more questions. I figured out that he probably is really allergic to these foods, even though I didn't realize it before.

A good example is the almonds. Michael had been eating Honey Nut Cheerios without incident since he was less than a year old. Since there didn't seem to be a problem, I didn't eliminate the Honey Nut Cheerios from his diet after his peanut allergy diagnosis (at the age of 1 year) or after his postive RAST test to almonds. However, the next time he ate them, I asked how he felt. He said that his tummy had hurt a little after eating, but it wasn't bad enough for him to think to tell anyone. If I hadn't asked the question, I never would have found out that he was probably having a very, very mild reaction. Needless to say, Honey Nut Cheerios are now off limits.

Everything I have read indicates that skin and RAST testing just provide an indication of the potention for an allergy, but that actual ingestion (i.e. food challenge) is the true test of the existance of the allergy. My advice (disclaimer - I am just a mom with no medical background) would be to continue to feed your son those foods to which he has tested positive, that he likes, and that he doesn't seem to react to, but monitor him carefully. If you notice any sign of a reaction to these foods, then you can evaluate whether to eliminate the food or just restrict the portions. Based on my son's test results, his real world experiences, and the potential, in general, for anaphylactic reactions to certain types of foods, I have now elected to eliminate peas and tree nuts. I allow small amounts of soy and green beans. This is still a learning process for me.

Sarah - From what I have read, the biggest concerns are the possibility of an severe reaction to the test and the possibility that the exposure will lessen the chance of ourgrowing the allergy. I personally have no problem with the skin prick test for my son. I say that because I do not believe that he will have an adverse reaction to the test based on his past experiences and I also don't believe that he has a chance of outgrowing his allergies so the exposure is not a problem.

I have never questioned my allergist about them so I can't really help you with much "expert" advice. As mentioned above, I don't think that either test ALONE is proof of an allergy. Both have the potential for error. My allergist did say that the skin test can often give false positives after the allergy has been outgrown (this was also mentioned in the link kkeene provided). Apparently, the skin can continue to stay sensitive. My allergist performed the skin test first, then when the result was postive, he did the blood test to confirm. I don't really plan of having either test performed often since I don't think that the end result will change (he will still be allergic to the foods). I personally don't know that the trend up or down in the numbers is really that meaningful - I won't change what I do based on a trend. I do agree with Jason in that I would want to have both numbers (skin and blood) to review prior to deciding to perform a food challenge.

On Nov 17, 2005

My 5yo daughter had a skin scratch test last week (was diagnosed with PA in Nov of 2002 - no exposures since then.) Within five minutes, she had a huge itchy hive where the PA was (histamine and control were normal). Her allergist (who is a very sweet man whose own daughter was just diagnosed with PA and shellfish allergy - how's that for cruel irony) came in and said that this does not bode well. Five more minutes later (10 out of 20 had passed), he came in with an Alavert for her to dissolve under her tongue and some cream for her back. So, she was still allergic to peanuts - see you in nine months. On our way home, she wanted to show me the school where one of her friends goes, so we drove over the river and through the woods and saw it. On our way back, she started to cry and complain that her back hurt. I figured she was still itchy, but when we got to the stoplight, I turned around and saw how red she was getting. She then started coughing this weird, wet cough that I had never heard before. When she wasn't coughing, there were gurgling noises. I pulled over in a parking lot, and got in the back to check her and could hear how her breathing was getting worse. Since we were much closer to the allergist

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