Too Clean for Our Own Good?
Why are allergies on the rise? How can children die by eating peanuts? An area allergist offers insight and advice.
On November 28, 2005, my office was bombarded with calls and questions after the national media began flogging a story about a Canadian girl who died after kissing her boyfriend, who had just eaten a peanut butter snack.
Parents were worried. Why should a harmless thing like a peanut (which is actually a legume, like a bean or pea and not a nut) cause illness or death to anyone, much less a high school girl after a kiss? With the recent release of several landmark studies from major allergy and immunology research centers, we are closer than ever before to a comprehensive answer.
Allergies have been increasing in the population for many years. No one knows for certain why this is happening, but there are several hypotheses. At this point, the most likely is a theory called the “Hygiene Hypothesis.” This is a complex theory suggesting that the human immune system is designed to deal with far more aggressive organisms than we find in the current, relatively aseptic environment that many people, particularly in prosperous countries, can create for themselves. In other words, our living conditions are too clean and too sterile for a body’s own good.
As our immune systems develop, it is important that we encounter infection. A somewhat delicate balance exists between immune activation and suppression, and amazingly, our bodies maintain that balance second by second. The allergic part of our immune system is designed to fight parasites, worms and other unpleasant creatures by which humans, prior to modern sanitation and the increased social fixation on cleanliness, were surrounded–creatures that are still found abundantly in less technologically developed nations. In the absence of those pathogens – and given certain genetic predispositions – our bodies have become over-sensitized to what are know as allergens, ordinarily proteins, that should pose little threat to humans. Recent studies suggest that about 20-25 percent of Americans today have allergies, reactions that can manifest as asthma, seasonal allergies, eczema or food allergies. Though the keeping of allergy statistics is a relatively new practice, researchers and practitioners widely agree that the current rate of people suffering from allergies represents a dramatic increase in only a few decades.
As unpleasant as all allergies may be, not all of them can kill. A runny nose or itchy eyes during the pollen season won’t cause most people to panic. But a deadly food allergy? That’s a big problem.
Although there may be some rare exceptions, food allergy almost always presents as food-induced anaphylaxis, which is a form of shock and is rapid in onset. The reaction may be limited to the skin, but may also spread to the lungs, heart and other organs. This can be potentially fatal and needs to be addressed quickly once suspected.
There are far more people who believe they suffer from a food allergy than actually do. Studies suggest that as many as 20-25 percent of people in the United States believe they have a food allergy. In fact, closer to eight percent of the U.S. population suffer from food allergy.
It is easy to understand why many patients who don’t have food allergies suspect that they do. I frequently see patients who complain of getting an itchy mouth from eating particular fruits or vegetables. This is, in fact, not a reaction to the fruit or vegetable, but a reaction to a pollen. The fruit or vegetable share some characteristics with the pollen to which that person is allergic and effectively fool the body into having a mild reaction. This usually manifests as mouth and throat itching or swelling which occurs quickly after the food is ingested. This type of allergy rarely is severe. It occurs in pollen allergic people and is usually not progressive (unlike true food allergy, in which each reoccurring episode may be worse than the last). Reactions can occur with many fresh fruits and vegetables but rarely with cooked products.
Most of these false food allergies can be predicted once the underlying pollen allergy is identified: Birch tree allergy can react with apple, apricot, carrot, cherry, kiwi, and plum, among others; Ragweed allergy may react with banana, cucumber, melon and watermelon. Grass allergy can react with cherry, peach, potato, and tomato, to name a few.
If you or your child is among the estimated eight percent of Americans suffering from a true food allergy, it is important that you talk to your doctor about it immediately. (It’s important to know that children have a somewhat higher incidence of food allergy than adults.) There are approximately 150 documented deaths per year from food allergy. Many of those who died might have been saved with prompt treatment.
An individual’s risk of dying of a reaction to food may be higher if that person has other medial issues, such as asthma. Other patients may be at risk because, where the first sign of most food allergy is a rash, they have no skin symptoms; instead, they suffer with little warning from a swollen tongue and a closing airway. In such cases, even people who carry an emergency syringe of epinephrine may be too slow to administer the medicine. The most important factor in surviving anaphylaxis is early recognition and administration of injected epinephrine.
The major allergenic foods for kids, accounting for greater than 85 percent of food allergy in children, are milk, egg, soy, wheat and peanuts. For adults peanuts, tree nuts, shellfish and fish are more prevalent causes of allergy. Most children will outgrow milk, egg, soy and wheat allergies, but only 20 percent of children will likely outgrow peanut allergy. A recent study of allergic reactions to tree nuts–such as almonds, walnuts, cashews, hazelnuts and pecans–similarly found that only about 20 percent of patients will “outgrow” their allergies to these foods.
Why are certain foods more commonly associated with food allergies than others?
In fact, any food can be an allergen. That said, allergens are almost always proteins, not fats, carbohydrates or other substances. Simple proteins, such as in a peanut, are more likely to persist as allergens because they are less easily broken down by digestion. In general, single food allergy is more common that multiple food allergy, meaning people are more likely to be allergic to one food rather than many. Though it receives a fair amount of media attention, preservative and additive allergy is exceedingly rare.
On last investigation, the Pioneer Valley was in the top ten of the worst allergic areas in the country. This may be a particularly bad year for us thanks to early warm temperatures and inadequate rainfall.
Allergy has become a major issue for many in the last decade, garnering much attention in the media. In addition to a variety of new drugs that may help relieve some allergy symptoms, the market has become full of products that purport to decrease the amount of allergens in a particular indoor environment. To an allergy sufferer, these products may seem reasonable, and while some of these interventions, such as dust mite covers on mattresses and pillows, may be helpful, most of the high priced products won’t help and may be potentially harmful.
If you or your child suffers from an allergy, the best place to start is to consult a well trained, certified and experienced allergist to can help you identify the source of your allergy and begin to treat it.
Dr. Jonathan Bayuk is a Board Certified Allergist and Clinical Immunologist and sees patients in our offices in Northampton, Westfield and Springfield.