Peanut Allergy Treatment

Feb 4, 2014

By Trevor Shewfelt, Pharmacist at the Dauphin Clinic Pharmacy


This isnt a mile high club story, but I was once in an airplane bathroom with a young, cute blond girl. It was my daughter Emily and she was about 4 months old. Her diaper needed to be changed. So I kinda wedged myself in such a way that my back was against the toilet and my knees were against the bathroom door. I did this so I could change Emily on my lap. The diaper change went okay, but after it was over I realized my legs had cramped and gone numb in this awkward position. I was now effectively trapped in an airplane bathroom with my infant daughter.

People with allergies to foods like peanuts can feel trapped too. Allergy to peanuts is thought to affect 0.5-1.4% of children in high-income countries. Peanut allergy is the most common cause of severe and fatal food allergies. It is hard to determine ahead of time which people with peanut allergies will have the most severe reactions. Although it is possible that someone's peanut allergy will go away over time, it is still uncommon.

When we talk about severe and fatal food allergies, we are usually talking about anaphylaxis. Anaphylaxis is a severe, sudden and potentially lethal allergic reaction. It is most often an allergic reaction to foods, medications or insect stings. After exposure to the allergen, anaphylaxis starts when white blood cells called mast cells and basophils release large amounts of chemical signals into the blood stream. One of the chemical signals is histamine, but there are many others. These chemical messengers affect almost every part of the body. They can cause all the blood vessels of the body to open up at once which means there is now not enough blood to fill all the blood vessels. This leads to there being not enough blood for your heart to pump around. Some of the fluid in the blood may also leave the blood vessels and leak into the tissues. Between these two problems the patient gets hypovolemic shock which can be fatal. In addition to the heart and circulation problems, anaphylaxis chemical signals can affect the lungs and airways. Anaphylaxis can cause the upper airway, the mouth and throat, to swell shut. Anaphylaxis can also cause the lungs to spasm. So with the potential to shut down the breathing and the blood flow it is easy to see why anaphylaxis can kill and kill quickly.

If you or your child has an anaphylactic reaction to a common food ingredient like peanuts, the first thing you are told is to avoid the allergen. This is easier said than done. My niece has a peanut allergy. She is 8 and an expert on telling you what things have peanuts in them. She also wont eat anything new unless her mother double checks the label to make sure it doesnt have peanuts in it.

If you have severe food allergies, like an allergy to peanuts, you have to carry an EpiPen. An EpiPen will let the child or caregiver give epinephrine to the person with the severe allergy before they die. Yes it is that serious. Yes, when in doubt just give the EpiPen. There is very little chance of harm from an EpiPen. There is a very great chance of harm from anaphylaxis. And anaphylaxis can progress from nothing to death in minutes.

So, although manageable, you can see how life with serious peanut allergies like my niece has can be daunting. Unfortunately, there can be near constant worry and anxiety over food choices. Accidental exposure to allergens does happen. The quoted rates say from 14-55% of people with peanut allergies get accidentally exposed to peanuts and have some kind of reaction every year. So it would be great if we could modify the disease so accidental exposures to peanuts werent such a big deal. The answer may be immunotherapy.

Immunotherapy isnt new. It has been around for people with allergic rhinitis and insect venom allergies for years. At our pharmacy we get small vials of insect venom sent to us from a specialized lab. The venom is diluted according to direction from the allergist and the patient gets injections on a regular schedule. The idea is that under the tight control of an allergist, a doctor with post graduate training in immunology and allergies, if we give the patient tiny amounts of the insect venom they are allergic to, their immune systems will get used to it. The if the patient is then stung by the insect, his/her immune system wont immediately freak out and go into potentially lethal anaphylaxis.

In the January issue of the Lancet, Katherine Anagnostou et al. published a study in which they did immunotherapy on peanut allergic children in Britain. The researchers used oral immunotherapy instead of the injections that are used in insect venom immunotherapy. Oral treatments are more convenient and previous attempts at injections under the skin to desensitize patient to peanuts had problems.

The researchers took 99 children aged 7-16 who were allergic to peanuts and gave half very small doses of peanut protein in a peanut flour and the other half got nothing. This was not a blinded trial, so patients knew if they got the treatment or not. The treatment group had their peanut protein dose slowly increased from 2 mg to 800mg. The peanut protein flour was mixed in with food and eaten. This oral immunotherapy treatment lasted 26 weeks. 62 % of the treated children had no reaction to 1400 mg of peanuts at the end of the trial. This was the primary outcome, desensitization. 84% of treated children were able to tolerate 800 mg of peanut protein at the end of 26 weeks. That means they could eat about 5 peanuts and not have anaphylaxis or other really severe reactions.

So this is a good and promising trial, but it is not the end all and be all. 99 children is still a small trial. The trial wasnt blinded. Only 64% of the children were completely desensitized. Even if desensitization worked, it has to be continued every day, or the fully fledged anaphylactic reactions will come back. This study gives us another small piece of the peanut allergy puzzle. It also gives hope that one day people like my niece wont have to obsessively read food labels and carry an EpiPen everywhere. But it is still too early for all people with peanut allergies to be tried on oral immunotherapy. Unfortunately, my niece will be in her food allergy trap for a while longer.

As my daughter is now 12 years old, it is very fortunate that we are not both still trapped in an airplane bathroom. I really thought for a while I was going to have to scream for help and get a flight attendant to release us from that airplane bathroom. But I did manage to slowly wiggle myself free from in between the toilet and the door. I didnt even drop infant Emily. On more recent plane trips, I have noticed folding change tables in airplane bathrooms. Although they came in too late for Emily and I, they are fantastic safety features to protect new dads and their children from bathroom entrapment.

The information in this article is intended as a helpful guide only. It is not intended to be used as a substitute for professional advice. If you have any questions about your medications and what is right for you see your doctor, pharmacist or other health care professional

We now have this and most other articles published in the Parkland Shopper on our Website. Please visit us at www.dcp.ca

As always if you have any questions or concerns about these or other products, ask your pharmacist.

Lancet article - www.thelancet.com/journals/lancet/article/PIIS0140-6736(13)62301-6/abstract

Health Canada Peanut Allergies - www.hc-sc.gc.ca/fn-an/pubs/securit/2012-allergen_peanut-arachide/index-eng.php

 

 


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