Food Allergy
Often, patients come in telling us what foods they are allergic to on the basis of allergy testing done years previously.
On history, they avoid these foods, but have no problems when they are eaten accidentally. It’s quite possible that they
are not allergic to those foods at all. Allergy testing is very accurate when we test for dust mites, mold, and pollen. But
it's less accurate when we test for foods, especially to foods that a patient doesn’t even think they’re allergic to. Years
ago, many allergists, even those board certified by the American Board of Allergy & Immunology, would give patients
instructions to avoid foods just on the basis of skin test results. Luckily, this is rarely done today. The most reliable way
to confirm a food allergy is with a food challenge. This test involves giving a capsule to a patient which contains either
the food which they suspect or something harmless (a placebo). To ensure the objectivity and validity, the patient (and
often the doctor) doesn’t know which capsule they receive.
Reactions can range from immediate itching or swelling of the lips and/or tongue, to hives, coughing, and wheezing.
These usually happen within a few minutes after eating the food, sometimes up to an hour. But some true food allergies
cause stomach cramping and diarrhea hours later. Unfortunately, there are no safe and effective forms of allergy shots
or allergy drops for food allergy at this time.
Food allergies can be life-threatening, especially if one is allergic to peanuts, shellfish, or tree nuts (walnuts, pecans,
etc) Besides avoiding these foods, the doctor should prescribe an injector device with epinephrine (adrenaline) to be
available at all times. There are two reliable devices: EpiPen® and Twinject. Epinephrine doesn’t have a long shelf life;
the devices leave the factory with an 18-24 month expiration date. Make sure that the one you buy has at least 12
months left until it expires. You often get the freshest EpiPen® or Twinject at 24 hour pharmacies. Twinject has a $20
rebate at www.twinject.com . Having said all that, if anaphylaxis occurs and all you have is an expired device, good
research shows that it’s still worthwhile using it.
A careful distinction must be made between "food allergy" and "food intolerance". Many people have lactose
intolerance, which causes gastrointestinal symptoms upon eating milk products. Lactose is the sugar in milk, and if you
don’t have the enzyme to digest it, these symptoms can arise. Other examples of food intolerance include headaches
from drinking wine or a runny nose from eating spicy foods.
Preventing Food Allergies in Children
Laura is one of our patients and is planning her first pregnancy. She has allergies and mild eczema, and her husband
has food allergies. They came to see me and asked what advice I had to decrease the chances that their baby will have
allergies.
First of all, there is no good evidence that avoiding specific foods during pregnancy will prevent the baby from
developing allergies, except maybe in the case of peanuts. The literature is inconclusive, but we now recommend our
pregnant patients with allergies to avoid eating peanut products while they’re pregnant. But what about a food that has
no peanuts but whose label says “this product may contain peanuts.” With the new food allergy rules passed recently by
Congress, some manufacturers put that label on everything they make; probably on the advice of their legal department.
Anyway, that would be a trace amount, so it would be OK for Laura to eat that food.
After delivery, the most important intervention is exclusive breastfeeding for the first four to six months of life. While
breastfeeding, Laura has been advised not to eat peanuts or tree nuts (e.g. walnuts, pecans, cashews). Some advise
eliminating eggs, milk, fish, and shellfish, but the evidence for avoiding those is sketchy. When foods are introduced to
the infant, dairy products should be delayed until 12 months; eggs until 2; and peanuts, tree nuts, fish, and shellfish until
3.
Breastfeeding while eating a restricted diet doesn’t always prevent food allergies in the infant, but it probably does
decrease the chance of the baby developing eczema. Some research has shown that young children with atopic
dermatitis (A.D.) develop allergic rhinitis and, subsequently, asthma much more frequently than young children without
childhood A.D. This phenomenon is called the Atopic March. Laura and her family are hoping that following these
recommendations prevent the misery of allergies in their children.
Note: Information contained in this article should not be considered a substitute for consultation with a board certified
allergist to address
individual medical needs.
Often, patients come in telling us what foods they are allergic to on the basis of allergy testing done years previously.
On history, they avoid these foods, but have no problems when they are eaten accidentally. It’s quite possible that they
are not allergic to those foods at all. Allergy testing is very accurate when we test for dust mites, mold, and pollen. But
it's less accurate when we test for foods, especially to foods that a patient doesn’t even think they’re allergic to. Years
ago, many allergists, even those board certified by the American Board of Allergy & Immunology, would give patients
instructions to avoid foods just on the basis of skin test results. Luckily, this is rarely done today. The most reliable way
to confirm a food allergy is with a food challenge. This test involves giving a capsule to a patient which contains either
the food which they suspect or something harmless (a placebo). To ensure the objectivity and validity, the patient (and
often the doctor) doesn’t know which capsule they receive.
Reactions can range from immediate itching or swelling of the lips and/or tongue, to hives, coughing, and wheezing.
These usually happen within a few minutes after eating the food, sometimes up to an hour. But some true food allergies
cause stomach cramping and diarrhea hours later. Unfortunately, there are no safe and effective forms of allergy shots
or allergy drops for food allergy at this time.
Food allergies can be life-threatening, especially if one is allergic to peanuts, shellfish, or tree nuts (walnuts, pecans,
etc) Besides avoiding these foods, the doctor should prescribe an injector device with epinephrine (adrenaline) to be
available at all times. There are two reliable devices: EpiPen® and Twinject. Epinephrine doesn’t have a long shelf life;
the devices leave the factory with an 18-24 month expiration date. Make sure that the one you buy has at least 12
months left until it expires. You often get the freshest EpiPen® or Twinject at 24 hour pharmacies. Twinject has a $20
rebate at www.twinject.com . Having said all that, if anaphylaxis occurs and all you have is an expired device, good
research shows that it’s still worthwhile using it.
A careful distinction must be made between "food allergy" and "food intolerance". Many people have lactose
intolerance, which causes gastrointestinal symptoms upon eating milk products. Lactose is the sugar in milk, and if you
don’t have the enzyme to digest it, these symptoms can arise. Other examples of food intolerance include headaches
from drinking wine or a runny nose from eating spicy foods.
Preventing Food Allergies in Children
Laura is one of our patients and is planning her first pregnancy. She has allergies and mild eczema, and her husband
has food allergies. They came to see me and asked what advice I had to decrease the chances that their baby will have
allergies.
First of all, there is no good evidence that avoiding specific foods during pregnancy will prevent the baby from
developing allergies, except maybe in the case of peanuts. The literature is inconclusive, but we now recommend our
pregnant patients with allergies to avoid eating peanut products while they’re pregnant. But what about a food that has
no peanuts but whose label says “this product may contain peanuts.” With the new food allergy rules passed recently by
Congress, some manufacturers put that label on everything they make; probably on the advice of their legal department.
Anyway, that would be a trace amount, so it would be OK for Laura to eat that food.
After delivery, the most important intervention is exclusive breastfeeding for the first four to six months of life. While
breastfeeding, Laura has been advised not to eat peanuts or tree nuts (e.g. walnuts, pecans, cashews). Some advise
eliminating eggs, milk, fish, and shellfish, but the evidence for avoiding those is sketchy. When foods are introduced to
the infant, dairy products should be delayed until 12 months; eggs until 2; and peanuts, tree nuts, fish, and shellfish until
3.
Breastfeeding while eating a restricted diet doesn’t always prevent food allergies in the infant, but it probably does
decrease the chance of the baby developing eczema. Some research has shown that young children with atopic
dermatitis (A.D.) develop allergic rhinitis and, subsequently, asthma much more frequently than young children without
childhood A.D. This phenomenon is called the Atopic March. Laura and her family are hoping that following these
recommendations prevent the misery of allergies in their children.
Note: Information contained in this article should not be considered a substitute for consultation with a board certified
allergist to address
individual medical needs.
The Allergy Clinic
Specialists in Allergy & Asthma Care
Specialists in Allergy & Asthma Care
