History: my son was tested for peanut in May because he reacted to Walnut. Skin prick test was positive. Up until that time he had tasted peanut butter and picked peanuts off dessert and eaten it. Don't know if he ever ingested peanutbutter or just had it on tongue. Also ate granola bars with peanut flour every day. Never any reaction whatsoever.
Had my son re-tested today with skin prick test because I had concerns with the validity of the last test. Was positive--4+. The most severe. I couldn't believe it. Doc said that means he is more sensitive--would react to smaller amount of allergen. But he's never reacted. Hmmm.
Then they said there could be a cross-reactivity with grass. Some grass has the same family of protein as peanut and since my son has some hayfever, allergic rhinitis, wheezing, maybe he's allergic to grass. We skin prick test for grass (my 4 yr old son screaming the whole time [img]http://uumor.pair.com/nutalle2/peanutallergy/frown.gif[/img] ) It's positive. This makes me hopeful that he is not really allergic to peanut. Doc could not give me statistics. Also, I've never heard of this. I saw something on the FAN conference notes about cross-reactivity with citrus fruit or something, but not grass. Will have to investigate further. Also saw somewhere here that peanut flour doesn't contain the protein, but doc said it does.
We didn't have the RAST test done like I planned because of issues with the lab. May get it done later. Doc thinks it's not necessary. I asked what if it were to come back neg? He said that wouldn't happen. I asked what if it were to back low? He would be very surprised if that happened. Basically just shrugged--wouldn't know what to think.
So is he allergic or not?? Highly sensitive/allergic on skin test, but never reacted. Allergic to grass which could cause pos skin test to peanut. Doc said that some people develop hayfever as adults, but were exposed as kids. I said I thought that if you eat a peanut and don't react, you aren't allergic. He sort of nodded and shrugged. Seemed to know his stuff, but didn't know what to make of this. Said he may not be allergic, and it could just be the grass. Unfortunately there is no way to know for sure until he eats a peanut. My only choice is to continue as though he is allergic, and see what happens some day when he accidently ingests peanut.
So frustrated but hopeful.....
On Jul 27, 2000
FRUSTRATION! I am sure these doctors just don't have all the answers but quess what they probably don't like to admit it. I am very curious to see how that rast test comes out. It sure would great if it was negative. I have been looking forward to my sons third bithrday also, just hoping those numbers will be gone but now I am not so hopefull.I think we are all new to these allergies to some extent and knowledge is the only thing that is going to keep us going and this web site of course. Take care Bonnie
On Jul 28, 2000
Just want to clarify about the peanut flour. I thought I saw somewhere that peanut flour doesn't contain the protein, but I searched here and FAN and it does. There was one story from a dad whose daughter reacted to something with peanut flour in it. Just didn't want anyone getting the wrong info from my first post. Also, now I KNOW he ate peanut flour nearly every day for 6 mos to a year and never reacted. What's a mom to think?
On Jul 28, 2000
Hi Ben's Mom
Many of the papers I have read comment on allergy developing with exposure or sensitization - since an allergy is your body defending itself from a protein or substance that is not usually harmful but that your body perceives as harmful. This is why you must first be exposed to the allergen before you become allergic - it is like getting sick with a virus and then developing some resistence to the virus.
Anyway, there is no "rule" that you will develop the allergy the first time you are exposed to the substance. There are many adults who develop allergies later in life after eating something all their life!
I just want to add that I can remember my daughter feeding peanuts to a squirrel at my mother's house 3 years ago and yet her second reaction was from merely touching a peanut shell two years later!
Mind you, it would be wonderful if your child were not really allergic and I wish you all the best.
On Jul 31, 2000
Perhaps you could explore a food challenge scenario with your doctor. In a hospital with medical personnel available you could introduce a tiny amount of peanut butter. Food challenges are often the answer if skin and rast testing is ambiguous. They are scary to contemplate though.
On Jul 31, 2000
Kathryn, I've thougth about a food challenge, but I haven't even had him RAST tested yet. And even if I felt comfortable with it and wanted to do it, I'm not sure I could find a doctor to do a food challenge on a kid with a 4+ skin test and maybe a high RAST score too. The allergist I went to never mentioned it. He just said I'd have to wait and see what happens when some day he accidentally has peanut.
I think I'm finally starting to come to terms with it and consider us to be lucky that he has never reacted. I think he's one of these kids that is a little allergic to just about everything, but not severely. I'm thankful he does not have asthma (wheezed once), no longer has eczema, and doesn't appear to react to most nuts, even though tested positive. After 2 months, I'm finally getting to a place where I'm accepting it for what it is--a lifelong peanut allergy. I may still have him RAST tested, I am still looking into a connection with grass (if he becomes desensitized to grass, would he be desensitized to peanut too?) etc. But I'm not feeling the frustration I was last week. Sorry to ramble!
On Aug 2, 2000
Well, here I go again. I keep posting to my own topic. I sent FAN email, and here is the email followed by their response. It's long, but I thought it was worth posting.
At 08:37 AM 8/2/00 -0700, you wrote: >Dear FAN, > >My allergist told me that grass allergy, specifically >Timothy and Burmuda grass, can cross-react with >peanuts. My son tested very positive (4+) on a skin >test to peanuts, but has never reacted. He also >tested very positive to both grasses. I have been >unable to find any information on this. Could you >tell me if this is true, and point me to some >articles/information on this? I'm not sure what this >means for my son's peanut allergy. > >Thank you.
Response: False positives are very common on tests for food allergies. An individual who can eat peanuts/peanut butter with no symptoms would not be truly allergic.
This article appeared in the October/November 1999 issue of Food Allergy News Copyright 1999 The Food Allergy Network
A Member Asks
"My son tested positive for peanuts, but never had any prior reaction. He had eaten peanut butter sandwiches three times a week. The doctor said he was just 'lucky' not to have reacted and we were told to eliminate all peanuts from his diet. Do you agree?"
The diagnosis of peanut allergy is increasing, owing both to a real increase in its occurrence and also possibly to misdiagnoses. Peanut allergy can only be diagnosed when characteristic symptoms (skin, gastrointestinal, and respiratory) occur within minutes to a few hours of peanut ingestion.
If your child eats peanut butter sandwiches three times a week without experiencing any symptoms, your child does not have a peanut allergy. In a sense, he has had negative peanut challenges thrice weekly. The presence of allergic IgE antibody to peanut is not sufficient to diagnose peanut allergy without the presence of symptoms when peanut is ingested. Allergic antibody to peanut merely raises the possibility that peanut allergy may exist; symptoms associated with peanut ingestion are necessary before diagnosis of peanut allergy can be suspected.
Studies suggest that somewhat less than half of those children below 3 years of age with positive peanut skin tests or peanut specific-IgE really have clinical symptoms on peanut ingestion. However, older children with peanut- allergic antibody may be proven allergic to peanuts.
Your child does not need to avoid peanuts, since he is not allergic to them. He should continue to enjoy and savor them.
Robert S. Zeiger, M.D. is a member of FAN's Medical Advisory Board. He is Chief of Allergy, Kaiser Permanente, San Diego; Clinical Professor of Pediatrics, University of California, San Diego.
This article appeared in the October/November 1995 issue of Food Allergy News Copyright 1995 The Food Allergy Network
ABCs of Allergy Testing by James P. Rosen, M.D.
Dr. Rosen is a member of The Food Allergy Network Medical Advisory Board. He is Assistant Professor of Pediatrics at the University of Connecticut School of Medicine and is in private practice in West Hartford, CT.
Adverse reactions to foods can be categorized as either a food intolerance or a food allergy (food hypersensitivity). The main difference between these two categories is that a food intolerance does not involve the immune system and a food allergy does. A food intolerance such as lactose intolerance is caused by an enzyme deficiency in the gastrointestinal tract.
Since many of the symptoms of adverse reactions to foods can be similar in both food intolerance and food allergy, how do you differentiate between the two? First and foremost, one needs to see a competent allergist trained in the evaluation and management of adverse reactions to foods.
The evaluation of a patient with suspected food allergy includes a detailed history, physical examination, and laboratory tests to detect antibodies directed against the suspected food. Antibodies are proteins that are found primarily in the bloodstream and function to help the body fight off invading organisms such as bacteria and viruses. The major antibodies are known as IgG, IgA, IgM, and IgE. Without these antibodies, we would die from overwhelming infection. One of these antibodies, IgE, is found in much higher concentrations in allergic individuals. IgE is extremely important in the development of the allergic response, like those seen in hay fever, atopic dermatitis, asthma, and food allergy. Although other antibodies such as IgG, IgA, and IgM are produced by the body in response to the ingestion of foods, the role they play in food allergy has not been clearly identified. Therefore, measuring these antibodies to specific foods has very limited usefulness. Thus, for diagnosing food allergy one should be concerned only about detecting specific IgE antibody to a food allergen and not about measuring IgG, IgA, or IgM to that food.
Allergens are usually proteins including food proteins such as milk or inhalant proteins such as pollens to which the body makes an immune response. This response in the allergic patient is to produce IgE antibody specific to that allergen.
Allergy Tests In order to evaluate patients with food allergies, proper identification of the allergen (food) responsible for the allergic reaction is crucial. To identify the food, detection of specific IgE antibody is essential. There are two primary methods to assess the presence of allergen-specific IgE antibody; skin testing and blood testing (Radioallergosorbent test, or RAST). Another blood test, the Enzyme Linked Immunosorbent Assay (ELISA) is primarily a research tool.
Skin testing is the preferred method over RAST testing to detect IgE antibody because it is simple, more sensitive, less expensive, and more readily available, and it appears to have a better relationship with clinical symptoms.
There is, however, a place for RAST testing in those patients who have a history of a severe life-threatening reaction to a food and one would not want to run the risk of having a systemic reaction to skin testing.
Also, one could certainly do RAST testing in young infants whose skin reactivity may be poor, or in those individuals who have such severe and extensive atopic dermatitis (eczema) that it is difficult to find portions of the skin that are clear enough for the proper placement and interpretation of the skin test.
Skin testing can be performed by two methods, known as the scratch, or prick skin test (PST), and the intradermal skin test (IST). The PST is the preferred skin test because it is less painful, more specific, and less apt to produce a systemic reaction.
The PST is performed by placing a small drop of the food extract on the skin and then scratching the skin lightly through the drop using a specialized probe or needle. The IST is done by injecting a small needle filled with an extract of the food allergen to be tested under the skin.
In both types of skin tests, if allergen-specific IgE antibody is present, a reaction similar to a mosquito bite occurs within 15 minutes. Intradermal skin tests are not used in the evaluation of food allergy, but are valuable for inhalant, insect, and drug allergy testing.
A positive prick skin test to a food only indicates the possibility that the patient will have a reaction upon eating the food. A negative PST to a food virtually confirms that the patient is not allergic to that food. The exception is in children under one year of age. For them, skin reactivity might be poor and the doctor may order a RAST test.
Therefore, the PST is an excellent test for excluding IgE-mediated food allergy but does not 100% confirm the presence of food allergy. A double blind placebo controlled food challenge (in which neither the patient nor the doctor knows whether each oral dose is the actual food or a placebo) is often needed to confirm positive skin test results.
Do Medications Interfere with Allergy Testing? Most antihistamines need to be withheld for about three days prior to skin testing. Antihistamines affect skin test results by interfering with the release of the chemicals that would cause allergic symptoms.
Conclusion Since many of the symptoms of adverse reactions to foods can be similar in both food intolerance and food allergy, the detection of IgE antibody to a food, combined with a history of symptoms and a physical examination, provides an excellent means of diagnosing food allergy.
This article appeared in the April/May 1998 issue of Food Allergy News Copyright 1998 The Food Allergy Network
Food Allergy Testing: Questions and Answers By Scott H. Sicherer, M.D.
Who should be tested for food allergy? Testing should be considered when symptoms such as hives, redness of the skin, itchiness, swelling of the lips or eyelids, throat tightness, wheezing, breathing trouble, coughing, vomiting, or diarrhea occur shortly after eating. Some chronic illnesses are sometimes associated with food allergy, including eczema (atopic dermatitis) and infantile digestive problems (significant vomiting, diarrhea). Asthma and hay fever are not commonly associated with food allergy.
What do the tests measure?
The tests determine the presence of IgE antibody directed to particular foods. (IgE is the allergic antibody which mediates most food allergy reactions.) Some laboratories offer other types of testing (cytotoxic testing, IgG antibody testing, provocation/neutralization, and others), but these should be considered unproven and experimental.
What types of tests are available? Two commonly used tests are blood (IgE RAST) and skin prick tests. The blood tests require a small sample of blood to be sent to a laboratory, where the amount of IgE antibody to the specific food is measured. The result is reported as a numerical value, or "class."
Skin tests are performed by exposing a tiny area of scratched skin to the food being evaluated. This is accomplished either by pricking the skin with a small needle or probe through a drop of the food extract, or by using a pricking device that has been pre-soaked in the extract. A positive skin test results in a mosquito-bite-looking reaction at the site of the test within minutes.
How are the tests interpreted?
The easiest test result to interpret is one which is negative; it is very unusual to have IgE-mediated reactions to a particular food when the skin or RAST test to that food is negative.
Unfortunately, the interpretation of positive tests is not so straightforward. Positive tests indicate that IgE is present but do not, in isolation, prove that a reaction will occur upon ingestion of the food. In fact, people who "outgrow" their food allergy usually continue to have a positive test result to the food for many years.
To further complicate matters, some proteins in foods are cross-reactive with similar allergenic proteins in non-foods (pollen) or in other foods. This cross reactivity can lead, for example, to a positive skin test for soy in a person with peanut allergy, or a positive test to wheat in a person with grass pollen allergy, even though the person has not had symptoms of an allergy to those cross-reacting foods.
Do the test results indicate the level of severity?
Neither the size of the skin test reaction nor the level of specific IgE antibody in the blood test necessarily correlates with the type or severity of symptoms. Consider an allergy evaluation with a "2+" positive skin test and a positive RAST test to peanut. One person with these results may be eating peanut every day without symptoms, while a different person may experience anaphylaxis from peanut. Similarly, that second person may experience only an itchy mouth on one occasion, anaphylaxis on another, and a mild case of hives on yet another occasion of peanut exposure.
The level of specific IgE antibody measured using a particular method of RAST test (CAP-RAST FEIA) reported in units called kUa/L, which indicates a concentration of specific IgE) was recently reported to be useful in determining the chance of true reactivity to certain foods. For example, an IgE antibody level of over 6 kUa/L to egg, over 32 to milk, over 15 to peanut, and over 20 to codfish were highly predictive (greater than 95% chance) of having some type of allergic reaction among highly allergic children. Unfortunately, lower values, unless virtually undetectable, may still indicate a potential for having an allergic reaction. This test may prove useful in following levels of particular IgE antibodies over time to see if they are falling (perhaps indicating that the allergy is being outgrown).
As you can see, the interpretation of these tests can be quite confusing. Your doctor must always interpret these tests in the context of the individual medical history. Even the selection of which foods to test must also be decided carefully and in the context of the medical history since up to one half of positive tests may not accurately reflect an allergy. Lastly, like any test in medicine, the results are occasionally wrong and should be repeated if an error is suspected.
Is there a definitive way to determine whether someone is or is not food allergic?
Oral challenge tests are definitive but carry a risk of serious reactions. These tests are conducted by giving gradually increasing amounts of the suspect food under a doctor's supervision while observing the patient for symptoms. These tests should be performed only by trained personnel, with emergency treatment immediately available. The tests might be used to verify the accuracy of a positive IgE test, to determine if an allergy has been "outgrown," or for a variety of other reasons. In cases of non-IgE-mediated reactions (some gastrointestinal allergies), an oral challenge may be the only definitive way to diagnose a food allergy.
In summary, food allergy tests are helpful in identifying or excluding food allergy as a cause of symptoms, but decisions regarding what tests to perform and how to interpret them are complex. Furthermore, removing foods from the diet or adding foods back to the diet can have serious medical consequences. Your doctor will interpret the test results within the context of your complete individual medical history and will use the results as just one of several pieces of information to guide in decision-making. Improved food allergy tests are in development and will, hopefully, provide more definitive results than those currently available.
Scott Sicherer, M.D., is Assistant Professor of Pediatrics in the Division of Pediatric Allergy and Immunology, Mount Sinai Medical Center, New York City.
On Aug 2, 2000
Hi Bensmom, Our child have some similarities. My daughter had a small reaction to a walnut last year. She earlier (that year) for the first time tasted peanut butter, but didnt really eat it, just put it on her tongue on piece of toast and then said she didnt like it. She had hazelnuts and almond cookies. But only had a few hardly visible hives around her mouth after eating a piece of whole walnut.
She skin tested positive to peanut, and walnut, but not to other nuts.
The grass thing didnt come into play, and she didnt have peanut flour, but probably had many "may contain nuts" products. Luckily, she never had any other reaction.
I sometimes wonder if she's really allergic or not too, but i obviously err on the side of the test. Assuming she is, we take all the precautions and have altered everyone around us lives (especially for b-day cakes). I mean most likely she is allergic (but i guess until i see her actually have a reaction, there's a part of me that just doesnt (or doesnt want to) believe she's really allergic!
But we couldnt possibly give her an oral challenge and have her possibly go into anaphyllaxis (even it is at a hospital).
So we go on, and hope she never has a reaction, and eventually a cure or something comes up! Best of luck, and keep posting any new info!
On Aug 2, 2000
BENSMOM - That is the greatest post I have read in a long time. The articles you forwarded from FAN were FANTASTIC....So many of my concerns/questions have been answered. I actually had also called my allergist last week and got some of the same type of answers, but this was GREAT!! My daughter is only 16 months old with PA, but we are going to have her re-tested in another year and a half or so..My doctor recommended CAP-RAST (to see if her score is low/lower) and then perhaps a skin/prick test. I pray she is one of the 10-20% who outgrow...however, since she did have a severe reaction on her 2nd exposure..who knows. Atleast I can look forward to the "cure" they are working on!! Thanks again.
On Aug 3, 2000
redtruck, I didn't know your daughter was so similar to my son. My son also reacted to walnut (swollen lip) and then was tested for everything. He was pos to almost every tree nut, but has eaten almond with no problem even though he was positive for it. Anyway, I try to keep track of the people with kids who have never reacted to see what everyone else is doing. I sometimes feel like I'm the only one who has trouble accepting this. I know dit's child has never reacted, and you and she seem to accept that a peanut could kill your children. I have trouble accepting this, but of course, at the same time, I don't want to take any risks.
The allergist I went to thinks a RAST test is unecessary. After reading the FAN article on the CAP-RAST I would like to have that test done and see how the numbers turn out. I also don't understand how you can be considered NOT allergic and still have IgE antibodies to peanuts. As far as oral challenge goes, I feel he was already sort of challenged with the peanut flour he ate in granola bars for months on end. But, with the positive test, it seems like even if he is considered not allergic now, he is predisposed to become allergic, which puts me back at square one. But, as I said, I still don't understand what it means to have the antibodies and supposedly not be allergic.
Thanks for your response, and yours too kathryn 65. I was starting to feel like I was talking to myself! Dit, dtaylor, and anyone else who has kids who have never reacted, I'd love to hear from you guys. What do you make of all this? Do you have trouble accepting this allergy?
On Aug 3, 2000
I have a question regarding all of this. I am sure many of you have heard of the statistic that 10-20% of kids outgrow this peanut allergy...Does anyone know if this applies to the kids that have tested positive BUT NEVER reacted (like you Bensmom). Or does it apply equally to children who have had a reaction and then grow out of it...Very curious....It seems easier to say that it would apply to the kids that never had a reaction in the first place....any comments
On Aug 3, 2000
My son tested positive level 4 to wheat on the skin prick test, yet he eats it all the time with no reaction. He is also level 4 to green beans with no reaction. The ped allergist thinks the wheat is a false positive and the green beans is a cross reaction to peanut (both legumes). His RAST is level 1 for wheat. Personally, if I were you, I would get the RAST done because it really could be negative.
On Aug 3, 2000
Scooby, thanks. Your experience really does make me want to get my son RAST tested. Actually, he tested pos for wheat, milk, and soy on a blood test, but eats them all the time. We keep him off cow's milk, but he eats yogurt and cheese.
Kathryn65, there was info on the FAN conference notes on this discussion board about what is a good sign for outgrowing the allergy. Isolated PA is one good indication. My son is allergic to lots of stuff, so that doesn't bode well for him. Since I guess kids who never react are not technically considered allergic, I'm not sure how these cases are worked into the statistics. Also, under "links" on this website, there is an article called "peanut allergy--where do we stand?" that talks a little bit about outgrowing the allergy. Hope this helps.
On Aug 3, 2000
BENSMOM, redtruck, et al... although my son has reacted to peanut, his reactions have been so minor compared to so many people's experiences I've read on these boards. They have also been so long ago, that I do wonder if he is allergic, too. He had his first reaction at 13mo. I was clueless about what was happening, and took him to the doctor's office right away. They gave him epi shot there, and we have been carrying epipen since, but we have never had to use it. He is 9yrs. old now. He had a very minor reaction at 18 mo. and an even milder one at 4yrs. old to a pastry with marzipan. Those times I gave him Benedryl and he was fine. It's now been 5 yrs since we've had any problem at all. And I know from reading these boards that I have not been nearly as vigilent as many people. I always thought we were careful, but now I feel that we've unknowingly taken so many risks--but without incident. He eats birthday cake, ice cream at ice cream shops, etc., etc. When he was a baby, his doctor didn't think I should have him tested for peanut--since he obviously had a reaction. But now, since he is 9, I'm wondering if I should. Any thoughts out there?
On Aug 3, 2000
I just received my FAN newsletter today and they had a long article about outgrowing food allergies. One thing that they mentioned was that "Compared with those who did not experience resolution of their peanut allergy, those who outgrew the allergy had smaller allergy skin tests, fewer allergic disorders (other food allergies, excema, astham), and no allergic reactions to peanut for about two years. The severity of the original reaction did not seem to affect the outcome." They said that the recent study that shows that roughly 5 - 20% become tolerant to peanuts was done in England and it focused on school-aged children who had experienced their peanut-allergic reactions as infants and young children (under 2 years old). It also states that children with sudden reactions affecting the skin, gut, or breathing may continue to have positive allergy tests even after they outgrow their allergy. Sorry this is so long but I thought some people may be interested if they don't get the newsletter. I do not have too much hope for my son outgrowing it since he is over the age of four and has had several reactions but obviously it happens for some kids and hope yours are the ones.
On Aug 4, 2000
Naomi, Thanks for the information. Sounds like it will give a lot of people hope. I personally don't really put much stock in the part that says kids who are diagnosed under 2 have a better chance of outgrowing. Maybe it's wishful thinking, but my son was never really exposed to peanuts under the age of 3, so how could he react or be diagnosed. Also, your post says that the British study was done on kids who had been diagnosed early, so it sounds like they don't have information on kids who are diagnosed later. Interesting stuff.
Did the article say how they know if a child has outgrown the allergy, since the skin test can still show postitive? Was it through oral challenge?
On Aug 4, 2000
Bensmom, It says that a "gradual physician-supervised ingestion of the food (oral food challenge) is the only way to determine if the allergy has been outgrown. Of course, it is a promising sign if the allergy skin test becomes smaller or negative or if the allergy blood test (RAST) is falling or becomes negative."