Wednesday, March 31, 2010

Food Challenges- What Are They, and Why is it So Hard to Get One?

With the awareness of food allergies increasing, there is expanded interest in the various methods of diagnosing food allergy. Of course, the skin test vs. blood test debate is ongoing. (I have more trust in the skin test, in case you're wondering.) There are also plenty of proponents of what I call "weird science". These are unproven methods that might make someone feel like they're getting an answer (and are certainly enriching the practitioner), but do very little to diagnose actual food hypersensitivity and, more often than not, lead to unnecessarily restrictive diets.

However, there's decidedly less discussion about what is considered the most definitive way to diagnose food allergy- the oral food challenge. A food challenge is a test that involves giving a patient incrementally larger doses of a specific food by mouth over a period of time, all the while monitoring the patient for signs and symptoms of an allergic reaction. Because the risk of an acute allergic reaction occurring during an oral food challenge exists, the test should be administered by trained medical professionals in a setting where emergency treatment can be immediately provided in the event of a reaction.

There are two main types of food challenge: blind and open. The type of challenge chosen for testing depends on what you are trying to determine.

In a single-blind challenge, the patient does not know which food he/she is being given to eat during the test. In addition to the food being tested, a dummy food is also offered, and the flavors and smells of both items are masked. This decreases the possibility of a patient reacting to the tested food on the basis of his/her belief that the food will not be tolerated, rather than due to a physical hypersensitivity. This is the test I might choose when I have a patient who is convinced that he/she cannot tolerate a particular food, but all the testing is negative. Although I might encourage the patient to resume eating this food, he/she will most likely be reluctant unless I can prove that it can be eaten without a reaction.

In a double-blind challenge, even the physician is not aware of which food is which until after the testing is complete. This method is used mainly in research studies, to reduce the risk of bias on the part of the individual recording the results. It is considered the "gold standard" in food allergy testing.

In an open challenge, the physician and patient are both aware which food is being tested. A placebo, or dummy food, is not required. Although this makes the test much simpler than a blinded placebo-controlled challenge, it does introduce a risk of bias. An example of how I use this test is when I suspect that a child may have outgrown a food allergy, but due to the severity of the initial reaction, I do not want to take the risk of reintroducing the food outside of medical supervision.

Food challenges can offer valuable diagnostic information when wading through the confusing world of food allergy, but they are underutilized. In fact, in some areas, it is difficult to find an allergist who is able to offer food challenges in the office setting. You may be forced to travel hours away to the nearest academic allergy center for food challenge testing.

Why? The truth is this- in the United States, the majority of health insurance companies will not reimburse the allergist for food challenges. The time spent (usually 2 to 4 hours) of measuring food doses, administering the doses, and monitoring the patient is generally bundled into the reimbursement for a 25-40 minute visit. Unfortunately, even though they would like to offer this testing method, most community allergists cannot afford to tie up a patient room and a nurse for this extent of time without reimbursement. This leaves many patients in the position of either finding an academic center, or continuing to avoid the suspected food allergen.

However, this may be changing. The American Academy of Allergy, Asthma & Immunology's committee responsible for food allergy is spear-heading an initiative to update the practice parameters for the diagnosis and management of food allergy. With the development of more defined protocols for food challenges in the office setting, it is possible that insurance companies may be convinced of the importance of food challenges, and the current barriers to the accessibility of food challenges in the community setting may be overcome.

Friday, March 19, 2010

Our Children Are Watching... the Way We Encourage Them to Behave!

Just went a local restaurant to pick up lunch. As I exited my car, I was shocked to see a mother shielding her ~4 year old son with the car door while he urinated in the parking lot- in the spot directly in front of the restaurant entrance!

I'm sorry, but this is inexcusable. You're not camping in the woods, you standing in front of at least fifty people behind glass walls. In a restaurant that has a bathroom, for goodness sakes! If your child cannot control his bladder, I understand- all children toilet train at their own pace. Sometimes, especially while you're learning, "I gotta go" means, "I gotta go NOW".

But parental actions dramatically impact what our children learn to accept as appropriate behavior.

People knock country music sometimes. but there are some lessons to be learned...
I was listening to a Dixie Chicks album in the car yesterday, and was struck by the following lyrics: "Our children are watching us, they put their trust in us, they're gonna be like us."

If you giggle while allowing your child to void in the entrance of a place of business, instead of picking him up and racing to the washroom that is no more than 30 feet away, you teach your children that it is acceptable to disrespect other people and their property.

Shame on you. And don't come crying to me when your kid gets picked up by the cops for vandalism in 11 years. You only have yourself to blame.

Wednesday, March 17, 2010

Son #1 Labels Son #2 a Trouble-Maker

Those who know my children personally know that Son #1 is cautious and thoughtful, and Son #2 is impulsive and and fearless. So, the following conversation seems especially intuitive.

Son #1: Mommy, I'm going on a trip to Mexico.

Me: Ooh... mommy wants to come!

Son #1: No, you can't come. It's a kids trip!


Me: Will you be taking your brother along?

Son #1: No- he can't come either. He's just going to run around all over Mexico and cause problems.

Sunday, March 14, 2010

Can We Go Overboard in Our Efforts to Protect Food Allergic Children?

Warning: This post will be controversial.

I have seen too many instances of terrified parents falsely believing that being in the same room as a peanut is going to kill their child. I have heard too much about 10 year old children being kept home from birthday parties, families being kicked off planes for requesting that peanuts not be served to anyone on board, of people demanding that high schools be peanut-free. I feel that something needs to be said.

The bottom line is this: there comes a time when we need to sit down and come to terms with the actual risk posed by inhalant exposure of peanut allergen vs. the perceived risk.

I do not need a double-blind placebo-controlled trial to tell me that the perceived risk of anaphylaxis to inhaled peanut protein far, and I mean FAR, outweighs the actual risk.

The majority of parents whose children have experienced food-related anaphylaxis are understandably traumatized by the event, and would go to the ends of the earth to prevent a repeat reaction. I get this. I personally know the nightmare of being doubled over in pain, covered in hives, and feeling my inside of my throat swell to the point that I had difficulty speaking. I am the mother of two allergic children myself, and was pleased when my son's daycare informed me they were peanut-free. To my mind, makes sense to exclude peanuts from a facility full of little kids with poor impulse control.

But I am saddened by the number of parents who wrongly have been made to feel as though the world is not safe for their children. Anaphylaxis sucks. But the vast majority of children with food allergy, even those who experience anaphylaxis with ingestion, are able to live safely in close proximity to their food triggers. Peanut protein is undetectable in the air after study subjects have consumed peanut butter. A study by Dr. Scott Sicherer (a highly esteemed clinician-researcher in the field of food allergy) evaluated 30 highly peanut-allergic children by having them sniff peanut butter for 10 minutes- none of the children reacted. This might be different with peanut flour, which could potentially trigger symptoms at points of contact: eyes, nose, lungs. However, this would be with close proximity, and is exceedingly unlikely to trigger the cardiovascular collapse associated with full-blown anaphylaxis.

So, why are so many parents telling teachers, school administrators, restauranteurs & airlines the following: "Don't you get it? My child could DIE!"

The answer is simple. Because they believe it.

At some point, a medical professional did an allergy test, gave the parents a lecture on the dangers of hidden peanut exposure, advised strict peanut avoidance, and trained the family in the proper use of autoinjectable epinephrine. None of these these are necessarily wrong.

The bad part is what's missing from the conversation. Where is the discussion about the actual risks of having peanut products in the home or school, the utility of peanut-free tables, of going out to a restaurant, of flying on a plane? What about the risk of eating those pesky "processed in a facility that also processes peanuts/tree nuts" items? This is where we, as a medical community, have let food-allergic children and their families down.

All too often, it seems easier and safer for the doctor to say- "Avoid peanuts at all costs. Here's an EpiPen- keep it close, and don't hesitate to call 911." Why unnecessarily risk a severe reaction, right? Seems logical enough. But it doesn't make things easier. It makes things harder. It FREAKS parents out.

The above statement, translated into parentese, is this: "Remember how your kid looked after eating that peanut butter cookie- all red and swollen and puking? If you're not careful- it'll happen again- might even be worse! Better be ready!" You think you're being cautious- but at what cost to your patient's quality of life? No wonder the parents are losing hair and gaining wrinkles over sleep-overs and school lunches and class trips to the state capitol! No wonder we have a new generation of children so ardently protected from any chance peanut encounter, however minute, that they've come to see the outside world as a danger zone!

This is counter to what we should be trying to accomplish as medical professionals. What is needed is a more nuanced, individualized discussion of risk, tailored to each peanut-allergic child. Parents need to know what to protect their children from, to be sure. They need excellent training in the indications and use of emergency medicine. But they also need to know which situations are relatively safe, even if it goes counter to the popularly held conceptions. This is where counseling from an allergist can be especially helpful.

It breaks my heart when I see parents who have not been adequately educated about the real risk involved with non-ingested peanut exposure, and have therefore been worried about scenarios that pose little to no risk to their children. As physicians, the onus is on us to do better by these families. All it takes it a little time, thoughtfulness, and a willingness to break free from a cookie-cutter approach to treating food allergy.

Thursday, March 4, 2010

Healthy Diet During Pregnancy Decreases Risk of Eczema and Wheeze in Baby

A Japanese study published in the European Journal of Allergy and Clinical Immunology (link: http://www3.interscience.wiley.com/journal/123251237/abstract?CRETRY=1&SRETRY=0) shows what many of us in the allergy world have suspected for a long time- mom's prenatal diet does have an impact of the risk of atopic manifestations in offspring at 16-24 months of age.

The study evaulated over 700 Japanese mother-child pairs. A diet-history questionnaire evaluated maternal consumption of fruits, vegetables, and antioxidants during pregnancy (at week 17). Atopic symptoms were evaluated based on criteria from the International Study of Asthma and Allergies in Childhood (at aged 16-24 months).

The study found that higher maternal intake of green and yellow vegetables, citrus fruit, and β-carotene during pregnancy was significantly associated with a reduced risk of eczema, but not wheeze, in the offspring. Maternal vitamin E consumption during pregnancy was significantly inversely related to the risk of infantile wheeze.

The authors concluded that maternal diet may reduce the risk of certain atopic manifestations in the offspring.

Although the results of this study are exciting, I do have a few concerns:

1) Self-reporting of diet history does introduce a risk of recall bias. Even in a scientific study, I fear that subjects are more likely to report a healthier than actual diet, the same way that we all tend to exaggerate to our physicians our actual rates of compliance with medication. So, if we're not actually having the patients write down what they are eating while they eat it (with a food diary, for example), are we really getting an accurate dietary history?

2) Because the study was done in a relatively homogeneous Japanese population, it doesn't account for genetic differences between different groups. We can't be certain that these results would be replicated in a genetically heterogeneous U.S. population.

These concerns notwithstanding, I still believe that this an important study, because it reminds us that what we put into our bodies has implications beyond our waistlines.

Future directions? I'd love to see a similar study done in a genetically diverse population, with a full dietary diary throughout the 9 months pf pregnancy. I'd also like to see this study done in multigravid women, so we can see if having a first child with atopy impacts the ability of diet to modify risk in a subsequent child.

As a mother of two allergic children, one with both eczema and wheezing, I'd be curious to know if my dietary choices played any role in my children's health. Full disclosure: Pregnancy #1- craved cottage cheese, yogurt, and produce. Pregnancy #2- craved cheeseburgers.

Guess who's itchy and wheezy?