Food Allergies
What’s The Difference Between Food Allergy Vs. Sensitivity or Intolerance?
A food allergy causes the immune system to activate and treat that food like an enemy invader. This causes a release of chemicals that lead to hives, vomiting, swelling of the face, difficulty breathing, and in some cases, dangerous drops in blood pressure. Some reactions are milder, while others are life-threatening (a combination of symptoms called anaphylaxis). They are usually fairly immediate after consuming the food, and require a strict avoidance of the trigger.
A sensitivity or intolerance is different. It doesn’t cause an activation of the immune response, so it isn’t life threatening. This doesn’t mean it isn’t bothersome. It leads to symptoms like indigestion, bloating, diarrhea, and abdominal discomfort. Your child can still consume the food, though they may not feel great after doing so. Most will cut the food out from their diet or use substitutes (Lactaid or almond milk for lactose intolerance, gluten-free grains for a gluten sensitivity).
When Do You First See Food Allergies? Who Is Highest Risk?
Usually, families start thinking about allergies (and doctors will start counseling on this) around the time of introduction of solid foods, which is anywhere from 4-6 months. The children at highest risk of food allergies are those with moderate to severe eczema, those with a strong family history, or those with “atopy” (which means they also have a diagnosis of eczema, environmental allergies, and/or asthma). Allergies can develop at all ages, though, including adulthood.
What Are The Main Allergens?
There are nine main allergens which tend to cause the majority of food allergies. These are milk, egg, peanut, tree nuts, soy, wheat, fish, shellfish, and sesame. This doesn’t mean that there’s not other foods that can cause allergies - there definitely are! It may just be harder to diagnose.
Should I Avoid Giving These Foods When Starting Solids?
In general, no! There’s a robust amount of research over the last few years supporting early introduction of allergenic foods, with evidence showing that it actually decreases risk of developing an allergic reaction in later childhood (see the LEAP Study). The newest recommendations are to introduce these “trigger foods” with the rest of solids (though I advise spacing each allergen a few days apart, so if there’s a reaction, we can narrow down the cause!).
Recipes: There’s lots of recipes for how to incorporate allergens into your infants diet online. I like this one from the Guidelines for Prevention of Peanut Allergy in the U.S.
Products: There are specialized brands (like Ready Set Food) that make the process for allergen introduction easier with premade recipes, as well as infant-friendly products (like Bambas, which are peanut puffs similar to Cheetos in texture). Talk to your doctor about if these would be good options for you!
Note: If your child has moderate to severe eczema, or if there is a strong immediate family history (e.g., mom, dad, sibling) of food allergies, I suggest talking to your PCP first. These children are higher risk for reactions, so some PCPs may refer to an allergist.
Introducing allergens at an earlier age can help prevent food allergies later in life.
Can I Get Testing to Predict What My Child Will Be Allergic To?
In general, guidelines don’t recommend screening for food allergies. The reason is that it can lead to a lot of “false positives.” This means that the test may suggest your child is allergic to something, even though they’ve eaten it multiple times without issues. If we accept these results as true (which some doctors might), it can lead to unnecessary restriction of your child’s diet, challenges with nutrition, and endless stress. It may also contribute to sensitivities to that food in the future. Given all of this, I advise that if there’s no reaction history, there’s no need to get tested unless you meet the severe eczema / strong family history criteria above.
What Are Signs of An Allergic Reaction? What If I See One?
If you introduce one of the major food allergens for the first time and notice a rash near the mouth, itchy or runny nose, a tingly mouth, or an episode of vomiting, stop giving that food, call your PCP regarding an antihistamine, and discuss further introductions of that food vs. referral to an allergist at the next visit. If there are more serious symptoms (severe vomiting / diarrhea, swelling of the lips or area around the mouth, difficulty breathing) or a combination of multiple mild symptoms, call 911, as this will require close monitoring of vital signs and treatment with epinephrine.
Once diagnosed with a food allergy, a really helpful tool is a Food Allergy and Anaphylaxis Emergency Care Plan. This one is free to download, can be completed by the allergist, and is given to the school nurse, daycare, or other caretakers so that they have a very clear outline of which medications to give if a reaction occurs and when they need to call 911.
How Does My Child Get Diagnosed?
If you have concerns about a food allergen, see an allergist for formal, thorough testing.
Oral Challenge: This is the most effective way to tell if there’s an allergy, though also the one that makes families the most wary! It involves an allergist giving small amounts of the food in question and monitoring for an allergic response. If there is one, medication is given and the challenge is finished. If there isn’t one, they give gradually larger amounts of the food (or different forms, such as scrambled eggs vs. a cookie that has baked egg in it) to see where the cutoff is for an allergic reaction to occur. This is helpful for creating clear guidelines for daycares / schools about what dietary restrictions should be implemented for your child.
Skin Prick Testing: While less accurate (there’s a 50-60% false positive rate), this is still a widely-used testing method for food allergies. The allergist places a few drops of a solution containing the allergen in question onto your child’s back. They then use a small needle to scratch the skin, allowing the solution to enter. While this sounds painful, it’s no different than scratching your own back. If a hive develops at that site, in combination with a history of a reaction after eating that food, it supports a true allergy (though may require further testing with an oral challenge to give a concrete diagnosis). If there is no hive, there’s a strong likelihood that your child isn’t allergic to the food in question.
IgE Serologic (Blood) Testing: This is also less accurate, though some allergists will opt for this instead of skin testing. It tests for the body’s antibodies to a specific food allergen, and results take a few days. It’s used in combination with the clinical history to discern if there’s an allergy, and may require additional testing to confirm.
What Happens After Diagnosis?
Once you have a diagnosis, you’ll get lots of guidance surrounding allergen avoidance, restrictions at school, and what to do if there’s another reaction. You’ll likely get prescribed an Epipen (an easy-to-use injection of epinephrine that stabilizes heart rate and blood pressure during a life-threatening allergic reaction). They usually come in a 2-Pack, in case the first syringe doesn’t work. It’s important to always carry this with you, and to know how to use it (there’s lots of videos online with instructions, and it’s fairly straightforward). The general rule of thumb is that if have to you use the Epipen, you need to go to the ER or call 911.
