Interview: Dr Chitra Dinakar & Dr Jay Portnoy, Proximity Food Challenges

Recently, the journal of the American College of Allergy, Asthma and Immunology published a letter in their Annals of Allergy, Asthma and Immunology from Chitra Dinakar, MD 
and Jay M Portnoy, MD of Children’s Mercy Hospitals in Kansas City, MO. In it, they describe the scores of patients they see with one overriding concern: fear of casual contact with their allergen. To that end they combed through the existing literature and created a simple solution to calm the fears of their patients with food allergy fears: proximity food challenge tests. I had an opportunity to interview them via email. Please read the below.

As always, consult with your medical health care provider for your needs and DO NOT DO THIS AT HOME unless directed by your medical health care provider.


Allergic Girl: What prompted your team to create the "Proximity Food Challenge Test"?

Dr Chitra Dinakar & Dr Jay Portnoy (MD): We observed that many children/individuals/families with food allergies appeared to be in a state of worry, not knowing when accidental contact with the trigger allergen will set off the dreaded, life-threatening anaphylactic reactions. They were experiencing significant impairment in their quality of life, with many of them making multiple adjustments and accommodations in the way they interacted at school and work, often resorting to sitting all by themselves at peanut-free tables (and allergen-free tables), and going to extraordinary lengths to avoid social situations where there might be exposure/casual contact with the suspected allergen. 

It was not hard to understand why they were doing it: published literature is conflicting, with some earlier reports suggesting a heightened risk of reaction on contact or inhalation of food allergens (e.g., peanuts) in public places such as airplanes and baseball games.

However, reassuringly, contrary to those reports, some recent studies (including those from our center), indicate that the risk of a severe reaction is largely related to ingestion or contact of the allergen with mucus membranes (and rarely, inhalation, such as with shellfish and aerosolized peanut dust), and not with casual contact on intact skin. Therefore, in order to address the concerns regarding the possibility of airborne and contact food sensitivity in individual patients, we developed the Proximity Food Challenge test at our center. This test helps them understand, in a safe and monitored setting, what to expect with similar exposure in a real world environment in the future.

AG: What is a "Proximity Food Challenge Test"?

Dinakar/Portnoy: In order to help children/individuals attending the food allergy clinics at Children’s Mercy Hospital determine the degree of sensitivity to casual airborne or skin exposure, (and based on the 2014 Food Allergy Practice Parameter Update recommendation to “Teach patients that ingestion, rather than casual exposure through the skin or close proximity to an allergen, is almost the only route for triggering severe allergic/anaphylactic reactions), we started offering the option of undergoing "Proximity Food Challenge Test".

Our approach, containing the key elements of the protocol described in a study by Simone et al, is adapted to be conducted in an office setting equipped to handle anaphylaxis. After obtaining verbal consent, the provider opens a jar containing the suspect allergen, often peanut (since it is the most feared) in the room. While conversing, the peanut butter jar is then brought increasingly closer to the child. If there is no reaction, a dab is applied on the patient’s arm, and the patient monitored. Five minutes later, the food allergen is washed off with soap and water.  In situations where there is heightened anxiety secondary to the perception of occurrence of a previous reaction, an attempt to mimic the scenario may be undertaken in a double-blind, placebo controlled fashion.

In our experience, the Proximity Food Challenge has helped alleviate fears of the families and enabled the child to integrate in the social network at school and in the community.

AG: Incredible! In your letter you state that “…misinformation regarding the triggers of anaphylaxis is widespread.” What are three of the most prevalent myths you hear in your practice at Children’s Mercy Hospitals and please correct them!

Dinakar/Portnoy: Myth 1: casual contact (through the air, on skin contact or just being in the presence of a trigger) will cause anaphylaxis that could be life-threatening.

This is a myth and is not true. In general, the food allergen needs to be absorbed into the body to cause a reaction. In other words, one has to eat a food or have it touch mucus membranes (e.g., inside of the eyes, nose) or broken skin (e.g., individuals with open sores, eczematous lesions) to have systemic symptoms and anaphylaxis. Other types of exposure can cause skin rashes and swelling of eyes, lips, fingers etc (and of course, can be extremely anxiety provoking), but typically does not cause anaphylaxis. Rarely, inhalation of aerosolized food allergen (as when shellfish is being cooked, or peanuts are shelled) can cause systemic symptoms.

Myth 2: Ingestion of a food you are allergic to will always cause life-threatening anaphylaxis.

In real life, most food reactions involve itchy mouth, rashes, hives, swelling of lips and tongue, or vomiting. Many commonly reported reactions to fresh vegetables and fruits are due to the plant proteins cross-reacting with pollens in the air (food-pollen syndrome), and is typically limited to symptoms around the mouth and throat and are not anaphylactic. 

However, reactions can progress to anaphylaxis and be life-threatening, therefore taking reasonable precautions to prevent exposure, and treat reactions, is strongly recommended.

Myth 3: Epinephrine is a dangerous treatment.

In fact, we all produce epinephrine. It is a natural hormone that is made in our adrenal glands (adrenal comes from the Latin for “near the kidney”. Renal = kidney. The adrenal is near the kidneys). Epinephrine, (commonly known as “adrenalin”), is naturally produced in our body when we get excited, or do a burst of physical activity. Epinephrine is therefore a safe drug that is extremely effective. Unfortunately, many folks prefer giving antihistamines such as Benadryl instead of epinephrine because of their fear that epinephrine is a dangerous treatment. This may be appropriate for very mild reactions only. If 2 body systems are involved or the patient is having difficulty breathing or low blood pressure, epinephrine should be given first. The sooner the better. If you wait too long (eg: more than 6 minutes) it will not work as well.

AG: Much of the currently published literature about allergens and casual contact involves peanuts, exclusively. For many with anaphylactic allergies to the other top allergens (tree nuts, dairy, eggs, wheat, soy, fish & shellfish), they worry that the studies about peanuts do not apply to them. How can they be reassured that studies about one allergen are safely extrapolated and apply to their needs/real risks?

MD: Casual contact with peanut does not cause anaphylaxis. That is also true for the other foods. The only exception is crustaceans (a subgroup of shellfish which also includes mollusks and cephalopods). Crustaceans like shrimp, lobster and crab, are often prepared by boiling. The vapors can carry allergens into the air so it is possible to have mild reactions in a seafood restaurant that prepares food that way. Also being within breathing distance when peanuts are being shelled, or any process that causes breakdown of the allergen and dispersal in the air, can potentially cause anaphylaxis.

AG: Proximity food challenges are an incredible idea and one that I hope spreads to other centers for excellence. Until that time, will you be expanding that idea/teaching it to other allergy/immunology practices?

MD: We are trying to spread the message. The first step is with this publication. When ideas are published after meticulous peer scientific review, they are accepted better by the medical community. We have already received encouraging positive feedback from a few colleagues regarding this manuscript.  We will try to spread the message at educational sessions at local, regional and national meetings. We have also written about this in Missouri Medicine.  Hopefully, the message will find its way to the lay community through blogs such as yours (thank you very much for your initiative!). Patients who have undergone this procedure have been very grateful for the lightening of their anxiety burden. Hopefully, they will also help spread the message and will advocate to food allergy support groups about the advantages of seeking this type of testing.

AG: How can patients advocate for themselves and ask for their allergist to implement this idea?

MD: Patients should ask the doctors to help them determine if casual contact is a trigger for their child. They should be aware that this will help them and their child integrate better in activities of daily living and in their social/cultural fabric. They should mention that they read about the proximity challenge being performed at other centers and request that the doctors contact us/read the article/read your blog to find out more information. It is a very simple procedure, and apart from being time-laborious, is not very hard to perform. Patients will most certainly find that the peace of mind they gain after the test is done is well worth their efforts.

AG: For anyone with food allergies feeling confused about allergist recommendations regarding avoiding contact with their allergens and how to do so without avoiding one’s life, how would you suggest they engage their allergist in a conversation about real risk versus low-to-no risk situations?

MD: I would suggest that they explain to the allergist that they would like to identify the types of exposure that are not life-threatening for their child/individual in order to better fit in at school/home/work settings. Getting this help from their allergist will help alleviate some of their anxiety.

AG: For allergists reading this, how would you suggest they better help / communicate real risk to patients?

MD: I think the allergist may want to consider bringing up the possibility during the clinic visit, and discuss the pros and cons of performing these challenges.


Thank you, Chitra Dinakar, MD 
and Jay M Portnoy, MD!


I think this is very important! Patients need to know their real risks!
This sounds like a great help. I know my daughter (who is now 21) could have benefitted from this when she was younger for sure. We are now going through peanut desensitization with a doctor near our area. We are excited and hopeful that this works for her.

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