Aug
31
2013

Peanut Allergies Are Deadly

Introduction

This article is about “peanut allergies are deadly”. In the US 1.5 million suffer from peanut allergies (Ref.1). People who have peanut allergies have to avoid peanuts and foods that contain even traces of peanuts lifelong. Here is a recent example of a 13-year old girl who died at a camp when she tried food contaminated with peanuts. Before we discuss peanut allergies in detail, we need to review first how the immune system is functioning.

How the immune system is primed to develop an allergy

Our immune system knows the difference between our own body components and substances that come from the outside. Scientists call this tolerance to our own surface proteins; and scientists call it an immune reaction that is mounting as a reaction to anything different from the surface antigens. There are different cells that make up the immune system. One of the main working cells of the immune system are the lymphocytes. A subtype are B cells that originate from the bone marrow producing antibodies when an immune reaction occurs. Antibodies fit like a lock and key to the surface of an antigen, in this case the peanut protein. T helper cells are T lymphocytes (thymus derived lymphocytes). They help the B cells to recognize the difference between the own protein components and the outside components.

IgE antibodies directed against peanut protein

There are also T killer cells, which when parasites or viruses enter the body activate them. With regard to peanut allergies, it is the B cells and T helper cells that interact. The B cells produce a powerful, very specific IgE antibody directed against peanut protein. There are memory B cells, which continue to produce these specific anti-peanut protein antibodies. They can cause severe allergic reactions when future exposure to peanuts (even traces) occurs. The more often a person allergic to peanuts encounters traces of peanuts, the more  the immune system gets boosted. This produces even more antibodies of the IgE type through reactivated B memory cells (Ref. 2). 98% of the population does not react to peanut exposure with allergies. But the other 2% who may have genetic susceptibility factors that predispose them to this often develop life-threatening reactions. These have the name “anaphylactic reaction”.

What is an anaphylactic reaction to peanuts?

The most extreme form of allergies involving IgE antibodies can cause anaphylaxis. In the beginning stages of a peanut allergy there may only mild symptoms such as hives on the skin, itching and tingling around the mouth, a runny nose, a scratchy throat, wheezing, stomach cramps, vomiting or diarrhea. However, with a more severe allergy an asthma attack can develop. In this case the blood pressure drops leading to fainting or shock. In addition, severe airway obstruction in the throat or lungs can cause suffocation.

I vividly remember an 11-year-old boy who arrived by ambulance in the emergency room of the hospital where I was working as the on-call physician. He had a hard time talking as his throat was swelling up as part of his anaphylactic reaction, within minutes he passed out completely (shock). Fortunately, an anesthetist was in the department and could intubate him very quickly.

Period of unconsciousness

However, despite adrenaline treatment, oxygen by artificial ventilation and high doses of corticosteroid drugs he did not wake up until 10 hours later. In retrospect it turned out that he had eaten some crackers of a familiar brand that he knew as being free of peanut flour. However, he saw an ad that the same brand of crackers was available as cheese crackers and he tried one of these. This prompted his admission to the hospital. The parents read the ingredients later: the label on the cheese crackers noted in small print that the flour of the cheese crackers contained peanut flour! Always read labels, even if it is a familiar brand! Fortunately for this boy he did not have brain damage from the time of his unconsciousness. He has been extremely careful since and is reading labels and avoiding unknown food items.

Peanut Allergies Are Deadly

Peanut Allergies Are Deadly

Cross-reactions between peanuts and other allergens

Allergies can be made worse when a person has inhalant allergies from pollens of trees or grasses that can share protein components from protein found in foods. The latest findings are that there are cross allergies between Fenugreek and lupine, which are both legumes, as are peanuts, so there are common antigens present in their proteins. A mouse-testing model has shed more light on this. Fenugreek has been shown to control mild diabetes by improving insulin resistance, but it cannot be consumed by persons who are highly allergic to peanuts because of the cross allergy mentioned.

There are other possible cross allergies to legumes like lentils, soy and chickpeas.

Other factors that can cause allergies to get worse

In the past the RAST test was often used.  This is a blood test for common food allergies that can cause severe allergic reactions like egg, milk, peanut, tree nuts, wheat, crustacean shellfish and soy. However, since about 2010 this has been replaced by the more sensitive ImmunoCAP Specific IgE test. Children who have food allergies to egg, milk, wheat, nuts, peanuts and soy often outgrow these allergies when they age, in other words their immune system can develop tolerance to many of these foods. Not so with peanut allergies! They tend to be very persistent.

Immune responses to food allergies are complicated

There are complications with immune responses to food allergies. They contained immediate type immune reactions and delayed type immune reactions. Allergists investigate the immediate immune responses with the above mentioned ImmunoCAP Specific IgE test. They can measure the delayed immune responses using the ELISA test. Positive IgE antibody tests for peanut protein are a marker that the person likely has more other allergies. An allergist should investigate them in that regard (Ref. 2).

New wheat varieties complicate the lives of people with allergies

What complicates the allergy sufferers’ lives even more is the fact that new wheat varieties were introduced. This happened in the 1970’s. The new wheat has the name Clearfield wheat. It has a much higher gliadin (gluten) and lectin content than the old wheat varieties. As a result of exposure to this new type of wheat gluten intolerance and leaky gut syndrome have increased substantially in the world population (Ref.3). In addition, genetically modified foods like soy, corn, sugar beets, canola and others have challenged the immune system of sensitive humans even more.

Autoimmune diseases from GMO food and modern wheat

We do know that some people can develop autoimmune diseases from GMO foods and modern wheat, and this may be the reason that a host of diseases that belong into this disease category (MS, rheumatoid arthritis, Hashimoto’s thyroiditis, ankylosing spondylitis etc.) are much more common now than in the past. The geneticists developing GMO foods were unaware how sensitive the immune system is.  The immune system detects a few different amino acid sequences in a protein mounting a strong immune response to it.

Treatment for peanut allergies

The key for sufferers from peanut allergies is to avoid exposure to it. Read labels and use common sense. If a food item has no label, do not attempt to eat it. Food manufacturers often mix peanut flour into the dough of crackers. But not every product has a label that identifies whether peanut flour is in it. Alternatively it says so only in fine print. With peanuts the antibodies usually circulate in the blood life long. The reason is that the B memory cells do not diminish and experience reactivation very quickly on repeat exposure. At this time they produce antibodies again. As exposure to peanuts can cause severe asthma or anaphylactic shock, it is important to carry an EpiPen with you and to know how to use it.

Oral immunotherapy

In Europe attempts have been made to develop an oral desensitization method for food allergies including peanut allergies, but it has not produced concrete results yet. Recently, however, research from Texas, USA showed that it is possible to desensitize patients with peanut allergy by oral desensitization. In Australia where food allergies are more prevalent than in the US, tolerance to peanut, nut and shellfish allergies is being pursued by oral immunotherapy. Another group in Australia has developed a vaccination method using peptides, which are a sequence of amino acids, but shorter than the full peanut protein. It appears that this is the future direction of treatment for peanut and other IgE allergies: a kind of vaccination treatment to induce competing antibodies, which will neutralize the allergic IgE antibodies.

Conclusion

Peanut allergies have become more troublesome as the food industry has mixed peanut flour into Thai sauces, drinks, cookies, crackers and such. The person allergic to peanuts must read food labels and eat as much single-ingredient natural food as possible. This goes against the tendency of food processors who produce foods with a long rat tale of ingredients. If you see a label “may contain nuts or peanuts”, stay away from this product, as it is safer. Always carry an EpiPen or Twinject with you, just in case you develop an anaphylactic reaction (you only have a few minutes to stop the allergic reaction with adrenaline). In the future vaccination with a peanut protein specific peptide vaccine as mentioned regarding the Australian research, will probably become the treatment of choice.

More information on status asthmaticus (an acute asthma attack).

References

1. Adkinson: Middleton’s Allergy: Principles and Practice, 7th ed. Chapter: Food Allergy. © 2008 Mosby.

2. Mandell: Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases, 7th ed.© 2009 Churchill Livingstone.

3. William Davis, MD: “Wheat Belly Cookbook. 150 Recipes to Help You Lose the Wheat, Lose the Weight, and Find Your Path Back to Health”. HarperCollins Publishers LTD., Toronto, Canada, 2012.

Apr
14
2013

Allergies Not Only In Spring

Springtime is the time of spring allergies: those affected develop a runny nose, itchy eyes and in more severe cases they may experience a flare-up of asthma. Allergies can be triggered by the increase of pollen counts in the air that occurs every spring. In those who are sensitive, this leads to antibody formation in the blood. But often people have not only sensitivities to the pollens of spring bloomers; they may also be allergic to spores from molds, to dust mites and may have underlying allergies to foods. The immune system has memory cells that memorize that a person has had an allergic encounter to one of these items in the past, and allergic reactions can become more significant with a future encounter. Allergies can also be made worse when a person has food sensitivities and there are cross reactions between pollens of trees or grasses that can share surface protein regions with similar protein regions in foods.

It is known that cross allergies are possible between birch pollen and apple, carrots or hazelnut. In its extreme form allergies due to antibodies, called IgE antibodies, can cause anaphylaxis. A person presensitized by inhaling birch pollen, after eating an apple, hazelnuts or a carrot can develop itching of the throat, swelling of the lips and very quickly deteriorate getting into an anaphylactic shock.

Other cross allergies exist between ragweed pollen, which is a powerful inhalant allergen and melons or bananas. Again there are specific IgE antibodies that are responsible for this immune reaction. In this case the ragweed allergy primes the immune system to produce IgE antibodies, which are potentiated by certain foods that share similar protein components as the ragweed pollen.

In the following I will deal with inhalant allergies separately from food allergies.

Allergies Not Only In Spring

Allergies Not Only In Spring

Inhalant allergies

Inhalant allergies are easier to diagnose and to treat than food allergies. Your doctor will likely refer you to an allergist when you have allergies that do not respond to treatment with intermittent over the counter antihistamines. Your symptoms may come on in the spring with itchy eyes and a runny nose. From year to year you find that you become more and more dependent on antihistamines and nose drops to unplug your nose. The allergist likely will do sensitivity tests, which consist of skin prick or scratch tests on the back or the forearms.

In more serious allergies, where the patient has coughing and wheezing attacks following allergic reactions, the allergist may suggest to start intermittent allergy injections alongside the standard inhalation therapy for asthma. An allergy serum is prescribed where the lab mixes ingredients based on all of the positive tests that led to a strongly positive skin reactions when allergy testing was done. Typically the family doctor or his nurse will start the allergy injections initially in weekly intervals, later when the maintenance dose is reached, it may be modified to injections every 10 to 14 days.

The allergy injections stimulate the immune system to produce harmless competing antibodies, which counteract the disease producing allergic antibodies. In the process of desensitization shots the immune system will normalize, which means that the inflammatory response of the immune system settles down to normal.

This is not the end of the story with inhalant allergies. The patient needs to be retested on a yearly basis by the allergist. The immune system changes all the time as new allergies can develop and old ones may go away.

Retesting is necessary to keep track of what is going on and to change the composition of the allergy serum. Those patients who are working together with the allergist can do very well, and often they gradually outgrow their allergies. Others may not be so lucky. They may have reactions to the allergy injections. In these cases avoidance of what causes the allergy may be the only solution to treat the allergies.

There is an alternative to allergy injections, which has been used in Europe, namely a sublingual immunotherapy. Recently there has been a review of the literature for FDA approval that is needed for oral desensitization for ragweed, dust mites, grass pollen and cat dander. It will take some time before the FDA approval process will become a reality for sublingual desensitization in the US.

A special form of inhalant allergies are allergies to pets (mainly dogs and cats, but also allergies to petting zoo animals). The dander that the human comes in contact with is a protein contained in the animal hair. It causes hives when it touches the skin. This occurs as the dander is absorbed through the skin and meets the local mast cells that release histamine. This in turn is responsible for the hive formation. Sneezing and even asthma can develop from inhaled protein particles that reach the lungs. Allergy injections for the treatment of animal dander allergies are very limited as they often do not help or make the allergies worse. Avoidance of animal contact is usually what the allergist recommends as the solution, a recommendation, which often is not appreciated by the affected animal lover.

Food allergies

Often we eat  some foods more frequently, because they are our favorites. This means that our gut lymphocytes that get in contact with these foods can start to react to one or more of the foods we ingest. At this time we may experience abdominal cramps, diarrhea, vomiting and a host of other possible symptoms.

The physician will tell the patient that testing for food allergies is a problem as most of the usual skin tests employed for inhalant allergies do not reliably work in determining food allergies. The doctor will ask the patient or the mother of the child with food allergies to keep a food diary and keep track of the allergic symptoms in the diary as well. An elimination diet will have to be devised based on the information gathered in the diary as it becomes clear from that record which foods cause which symptoms. The foods causing allergic symptoms are subsequently eliminated. This is a cumbersome process, but it is the most reliable method of testing and treating food allergies.

In the past there was a blood tests, called RAST test, which tested for common food allergies that can cause severe allergic reactions like egg, milk, peanut, tree nuts, wheat, crustacean shellfish and soy. Since about 2010 this has been replaced by the more sensitive ImmunoCAP Specific IgE test.

Children often develop food allergies to egg, milk, wheat, nuts, peanuts and soy, which are food allergies with positive IgE tests. When they age, their immune system develops tolerance to many of these foods and they often outgrow these allergies.

There are other popular lab tests where a blood drop is analyzed with IgG, IgM and IgE antibodies against a panel of foods. A number of suppliers offer these tests.  However, the specificity, sensitivity and reliability can pose problems with regard to the interpretation of the results: allergists often point out that a test may be a false positive when a person likes certain foods and IgG antibodies against this food show up despite the patient having no symptoms. Another specialist may interpret this to indicate that the body shows early sensitization to a certain food, but clinically it is not yet obvious. In other words the sensitivity of the test is so high that it undermines the validity of the test. Recently a panel of international scientists reviewed the validity of these IgG based food intolerance tests and they found the tests not reliable.

The immune responses to food allergies are complicated as there are immediate type immune reactions and delayed type immune reactions. The immediate immune responses are investigated with the above mentioned ImmunoCAP Specific IgE test. The delayed immune responses can be measured using the ELISA test.

Other considerations about allergies

You see from this discussion that a patient with allergies needs a properly trained allergist who will do a comprehensive analysis involving a thorough history, examination, blood tests and immune tests.  The test results have to be interpreted with the experience and the clinical judgment of the specialist.

Since the 1970’s when Clearfield wheat was introduced around the world on a large scale, which has a much higher gliadin (gluten) content than the old wheat varieties. As a result of exposure to this new type of wheat gluten intolerance and leaky gut syndrome have increased substantially in the world population. Genetically modified foods like soy, corn, sugar beets, canola and more have challenged the immune system of sensitive humans even more to an extent, which is not fully understood yet. We do know that some people can develop autoimmune diseases and this may be the reason that a host of diseases that belong into this disease category (MS, rheumatoid arthritis, Hashimoto’s thyroiditis, ankylosing spondylitis etc.) are much more common now than in the past.

After food elimination for 2 to 12 months depending on the severity of the food allergy, your body may have eliminated the allergy to the food you have avoided, in other words your body built up tolerance. Before you expose yourself to any food that you used to be allergic to and that you want to re-test, it is best to have an EpiPen ready in case your allergy has not resolved. Caution is necessary with regard to foods that cause more severe allergies, e.g. shellfish or peanuts, which may last life long. It is safer to avoid these foods that cause more severe allergies altogether.

Allergic reactions of the immune system belong into the category of chronic inflammatory diseases. These are known to be the root of chronic diseases like asthma, arthritis, heart disease, high blood pressure and cancer. When you are vigilant about allergies and get proper assessment and treatment by an allergist, you will prevent serious health problems including the above mentioned chronic diseases.

More on asthma, which is a chronic inflammatory lung condition, often associated with multiple environmental allergies:

http://nethealthbook.com/lung-disease/asthma-introduction/

Last edited Nov. 6, 2014