Introducing Allergens to Baby
Introducing egg, peanut, and other common allergens early and serving them often can help prevent food allergies from developing. Our Board-certified pediatric pros explain why—and how to safely introduce common allergens as soon as baby is ready to start solids.
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In 2015, a groundbreaking study demonstrated that the early introduction of peanuts to at-risk babies could reduce the risk of developing peanut allergy by as much as 81%. In other words, delaying the introduction of peanut could actually increase the likelihood of peanut allergies developing.
This landmark study led medical professionals to revise their recommendations around the introduction of peanut and extrapolate the findings to other food allergens as well. As such, allergists and medical institutions now recommend introducing many common food allergens well before a baby’s first birthday.
Allergies in children are on the rise
In the United States, food allergies in children rose an astounding 50% from 1997 to 2011 and the prevalence of peanut and tree nut allergies tripled during this time. Interestingly, this is roughly the same period of time in which parents were advised to refrain from introducing peanuts and other allergens until well beyond the first birthday. With the new guidelines to introduce allergens early, our hope is that the number of babies and children with allergies will start to decline.
Top food allergens for babies
Today, one in 13 children have a food allergy in the United States. Of those children with food allergies, 40% will be allergic to more than one food.
Although it is possible to be allergic to any food, the most common food allergens are those listed below.
Finned Fish
Shellfish
Soy
Tree Nuts
Is my baby at risk for food allergies?
There are two major risk factors that signal a baby may be at greater risk of developing a food allergy.
High Risk: Severe eczema. Eczema is a common childhood rash caused by a skin defect. It typically shows up as dry, inflamed, and intensely itchy skin patches. Eczema is thought to increase the chances of developing a food allergy via exposure through the impaired skin barrier. Severe eczema, in particular, is widely considered a significant risk factor for developing food allergies. Although there is no formalized international definition of severe eczema, most physicians consider eczema severe if it covers a large percentage of the body or persists for an extended period of time despite the regular application of moisturizers and topical anti-inflammatory medications. Note: Mild to moderate eczema is also associated with an increase in the risk of developing food allergy. That said, most medical professionals agree that well-controlled eczema of lower severity does not warrant any allergy testing or special precautions prior to introducing allergens at home. Babies with eczema of any severity can reduce the risk of peanut allergy by introducing peanut as early as 4 months of age.
Moderate Risk: Existing food allergies. Babies with an IgE-mediated food allergy to one food may have a higher risk of developing allergy to other foods. For example, babies with existing egg or cow’s milk allergies are known to be at an increased risk of developing peanut allergy. Note: there is not enough data to definitively state that existing allergy to other common food allergens (finned fish, sesame, shellfish, soy, tree nuts, wheat) is also associated with an increased risk of developing additional food allergies. However, allergists often take a proactive approach and recommend that these food allergens be introduced early and served often once an allergy is ruled out.
If baby has either of the above risk factors, work closely with your pediatrician, family doctor, or pediatric allergist early in your solid food journey. They can help you map out a plan to safely introduce potential food allergens, order allergy testing, or supervise allergen introduction in the clinic. Otherwise, aim to introduce the common food allergens once baby is ready to start solids and try to keep them in regular rotation at mealtime.
What about family history of allergy?
There is no strong evidence that a younger sibling of a child with peanut allergy, for example, is at a substantially increased risk of developing peanut allergy Allergy specialists now recommend that siblings of children with food allergies can introduce common food allergens at home without any pre-screening by an allergist if they are not at higher risk due to severe eczema or another pre-existing food allergy.
Studies suggest that deliberately delaying the introduction of food allergens in siblings of allergic children may put the younger sibling at increased risk of developing a food allergy. Essentially, the risk of delayed introduction is higher than the risk posed by family history. Nevertheless, if you are anxious due to family history, you may be able to request medically-supervised allergen introduction in a clinic - this is called an oral challenge.
How to introduce allergenic foods to babies
Introducing food allergens doesn’t have to be terrifying. You can start with a very small amount of the allergen to minimize any possible reaction and slowly work up to larger servings. For step-by-step guidance, download the Solid Starts App.
Tips for introducing common food allergens to babies
Start small. The smaller the quantity of allergen ingested, the less severe an allergic reaction may be. So start with small amounts. For example, mix 1/8 tsp of almond flour in porridge or swipe your fingertip in smooth peanut butter (honey-free) that has been thinned with water, breastmilk or formula, then let baby have a small taste. If there is no reaction, gradually increase the amount with each subsequent exposure. This can begin as soon as 10 minutes after the first taste, or can be increased more conservatively over the next few days. Once you’ve ruled out an allergy, try to offer the food at least once, but ideally 2 or 3 times per week, to help prevent a food allergy from developing.
Introduce allergens in the morning. Pick a day when you or a trusted caregiver are able to closely observe baby, and start shortly after waking or right after a morning nap. This way, in the unlikely event of a reaction, it may be easier to contact your doctor for guidance. Most reactions occur within minutes (but up to two hours) after eating, which is why it is best to introduce allergens when at least one adult can focus their full attention (without distraction from other children or activities) on baby for at least two hours.
One food allergen at a time. This way, if there is a reaction, you’ll know which food was responsible. This doesn’t mean you need to stop introducing other new foods during allergen introduction. It’s okay to offer multiple new foods each week, as long as you aren’t introducing common food allergens simultaneously. Just keep in mind: not all babies with allergies react on the first exposure. That is why it’s important to start with small amounts of an allergen until you rule out an allergy. A few days of eating small but increasingly greater amounts of an allergen is typically enough to establish that a food is well tolerated.
Regular exposure. Once an allergen is safely introduced, try to keep that food in regular rotation at mealtimes. Consistency is key: allergists often recommend serving food allergens at least once a week, and ideally 2 to 3 times a week if possible. Try not to stress if that pace doesn’t work, or if baby doesn’t consume an entire serving. Even eating small amounts (~2 grams of a food allergen per week) can help prevent an allergy from developing as long as it is offered consistently
Need help introducing allergens? Get the Solid Starts App for step-by-step guidance on introducing and regularly serving allergens.
Allergy FAQs
Should I only introduce one food at a time?
There is no evidence to support a need to wait 3 to 5 days between introducing new foods. In fact, this approach can significantly limit the timely introduction of different tastes and textures, and potentially increase the risk of food allergy in the future. In general, the benefits of introducing a variety of new foods outweigh the risks of a potential reaction or sensitivity.
However, for common allergens, it’s wise to introduce those on days when no other common food allergens are being introduced. This way, you can identify which food was responsible should a reaction occur.
What is an IgE-mediated allergy?
IgE-mediated allergies result in symptoms very quickly after allergen ingestion, often within minutes.
IgE-mediated allergies are diagnosed by confirming a clinical history of reactivity with a positive blood test or skin prick test at the allergist’s office. Several IgE-mediated food allergies are commonly outgrown in early childhood.
What is a non-IgE-mediated allergy?
Non-IgE-mediated food allergies are immune hypersensitivities that do not involve the production of IgE antibodies. Instead, other parts of the immune system, such as white blood cells, are activated. Symptoms typically take longer to appear than IgE-mediated allergies (from a few hours to days after eating) and they show up in various ways, including skin rashes and gastrointestinal symptoms.
There is no standardized testing available for non-IgE-mediated food allergies, so the diagnosis is based on clinical history. The recommended treatment? Avoid the allergen and reassess at regular intervals to determine if the allergy has been outgrown. Epinephrine and antihistamines will not treat symptoms of non-IgE-mediated food allergy. However, in certain cases, anti-nausea medication, steroids, and biologics may be used to counteract the bothersome symptoms and inflammatory response.
What is FPIES?
Food Protein-Induced Enterocolitis Syndrome (FPIES) is an increasingly recognized non-IgE-mediated food allergy in children that can be severe and life-threatening. Unlike most food allergy reactions that occur within minutes of contact with a specific food trigger, FPIES allergic reactions occur within hours after consuming a particular food. For this reason, FPIES is sometimes known as a delayed food allergy.
The most common food culprits are:
Cow’s milk products (such as infant formula)
Soy
Meats
Poultry
Seafood
Squash
The classic presentation of FPIES is an infant who recently switched from breast milk to formula or has started solid food. Baby typically begins vomiting between 1 to 4 hours and may also begin experiencing diarrhea between 5 to 10 hours after ingesting the trigger food. FPIES is extremely rare in exclusively breastfed infants.
Other symptoms include low blood pressure, low body temperature, extreme pallor, repetitive vomiting, and significant dehydration. Thankfully, most cases of FPIES will completely resolve during toddlerhood. Babies with FPIES should be in the care of an allergist/immunologist and are best served by a multidisciplinary team that also includes their general pediatrician or family practitioner, a pediatric gastroenterologist, and a registered dietician.
How much does baby need to consume to count as an exposure?
Don’t worry too much about volume. If your baby doesn’t consume the entire serving of allergen offered that day, that’s ok. Relatively modest quantities of allergen exposure (~2 grams of protein per week) can be effective for allergy prevention, as long as exposure remains consistent.
How should I reintroduce an allergen if baby has a reaction?
Consult your doctor before attempting to reintroduce any food that has triggered an allergic reaction in your child. If baby has experienced an allergic reaction to a food, do not offer the food again until you can make a plan with licensed professionals, ideally a pediatric allergist. Allergic reactions can be unpredictable, and a child who experienced only a mild reaction at first might experience a more severe reaction later on. Your medical team can guide you on how best to proceed, and they may recommend reintroduction under medical supervision. This way, baby can be monitored and immediately treated if an allergic reaction occurs.
Rash on baby’s face from tomato and other acidic foods
Acidic foods often cause a harmless rash on the skin that comes into contact with the juices These foods can include, but are not limited to:
Contact rashes typically show up around the mouth and chin, and usually dissipate with a gentle cleanse of the skin. Pat with a wet washcloth; don’t rub to avoid further irritating the skin.
To help protect the skin from contact rashes, apply a barrier ointment (pure petroleum jelly or a plant-based oil and wax combination) to the face before mealtime.
If I have allergies or Oral Allergy Syndrome, will I pass them on to baby in my breast milk?
Fortunately, allergies and Oral Allergy Syndrome (OAS) are not passed along to baby through breast milk. Concerns about potential food allergies should not discourage parents from offering breast milk, especially since breast milk offers a variety of nutritional and immune-supporting benefits for baby. Avoiding common food allergens either during pregnancy or when lactating hasn’t been shown to prevent food allergies
If I am allergic to a food, how do I introduce that food to baby?
Rest assured that you are unlikely to experience a serious allergic reaction from simply being in the vicinity of your allergen or even from handling it. Most patients with food allergies react only upon ingestion. That said, there are steps you can take to minimize your risk of a reaction.
When preparing the food, avoid prolonged skin contact with the allergen. If you cannot wash your hands promptly afterward, wear gloves.
If you have a carpet or rug, make sure you place baby’s high chair over a splat mat or move the high chair to a non-carpeted surface. You could also consider feeding baby outside. This is also a great time for disposable placemats, plates, and utensils.
When introducing the allergen, offer the allergen at the beginning of the meal and immediately follow up with another food to which neither you nor baby are allergic. This will reduce the allergen content in baby’s saliva.
After mealtime, clean baby’s hands and face thoroughly, wipe down the eating surface and chair, and remove baby’s clothing so it can be washed.
Lastly, try to stay calm, even if you are nervous at first. Children pick up on the feelings of the adults around them. With practice, offering your allergen to baby will get easier and become routine. If you feel very nervous, this is an excellent opportunity for a non-allergic parent, caregiver, relative, or friend to spend quality time with baby.
If baby was diagnosed with cow’s milk allergy, can they consume other dairy products like yogurt and cheese?
It depends. Cheese and yogurt contain the same allergenic proteins as cow’s milk, and they can trigger allergic reactions in sensitive babies. However, if baby is not highly sensitive to casein (the heat-stable protein in milk), they may be able to tolerate fully baked forms of cow’s milk in a biscuit, cake, or muffin. Some babies can also tolerate less extensively heated forms of milk in pancakes or waffles. However, this should be discussed with your healthcare professional before attempting it in the home setting.
Buffalo, goat, and sheep milk products are not recommended for babies with cow’s milk allergy due to high rates of cross-reactivity.
If baby has a non-IgE-mediated cow’s milk allergy and requires an alternative formula, your doctor may recommend skipping soy formula and going directly to an extensively hydrolyzed or elemental formula instead, as babies with this type of milk allergy often react to soy as well.
Research shows the majority of children with cow’s milk allergy will outgrow it by age 6, and many babies with milder symptoms of milk protein allergy—which can show up as painless blood in the stool—can successfully reintroduce cow’s milk as early as their first birthday, with the guidance of their doctors.
If a recipe requires milk, what is the best substitute for a baby with cow’s milk allergy?
The safest options are:
breast milk from an individual who is avoiding dairy and soy in their diet (although many babies with cow’s milk allergy do just fine with breast milk from an individual who consumes dairy products)
a hypoallergenic formula as recommended by your healthcare professional
Lactose-free infant formula and lactose-free cow’s milk are not appropriate for a child with cow’s milk allergy. In milk allergy, the whey and casein proteins trigger the allergic reaction, and lactose-free milk still contains these allergenic proteins.
For toddlers, fortified oat milk and pea protein milk are also acceptable substitutes as drinks. Note: Compared to cow’s milk, pea protein milk tends to be lower in calories, and oat milk is usually lower in protein. If you desire a source of mammalian milk for a toddler, mare’s milk and camel milk have relatively low rates of cross-reactivity with cow’s milk Be sure to connect with your pediatric healthcare professional, dietitian, or nutritionist to help identify the best substitute for your needs.
Do I need to buy specialty puffs or powders for allergen introduction and maintenance?
No. It is not necessary (and it is generally not cost-effective) to rely on powders or medicalized processed food products when introducing food allergens or keeping them in the diet. A food allergen may be introduced by safely preparing it in a way that meets baby’s age and developmental ability, and you can look up any food in our First Foods® database to see how it’s done. However, powders and puffs can help with allergen introduction or maintenance when there is limited access to food (while traveling, for example), or if baby has a medical condition that interferes with the introduction of solid food.
Food Allergies Around the World
The United Nations and World Health Organization have established the Codex Alimentarius (Codex), a set of international food standards, guidelines, and codes of practice designed to ensure the safety of the global food supply.
The Codex requires disclosure of the following food allergens:
Egg
Milk
Fish
Crustaceans
Gluten
Soy
Peanut
Tree nuts
Sulfites (at concentrations 10 mg/kg or more)
These foods comprise more than 90% of food-induced allergic reactions in most areas of the world. However, common food allergens vary worldwide and are influenced by genetics, the foods most consumed in those regions, and cross-reactivity with airborne allergens, among other factors.
Africa
Several African nations, including Egypt, Malawi, Morocco, and South Africa, have common food allergen lists that mirror that of the U.N./WHO Codex.
Recent research suggests that food allergies may be underdiagnosed across the African continent.
Asia
There is no central regulatory body governing food allergy labeling for the Asian continent, and common food allergens vary in different areas.
Common food allergen lists for China, Hong Kong, Singapore, Thailand, and Vietnam are similar to the U.N./WHO Codex.
Common food allergens in Japan and South Korea include allergens outlined in the UN/WHO Codex, as well as buckwheat.
Additionally, South Korea lists chicken, beef, pork, pine nuts, peach, and tomato as common food allergens.
While chickpeas are not designated as a common allergen requiring labeling, chickpea is a significant emerging food allergen in India.
Central America, South America & Caribbean States
CARICOM (an organization of Caribbean states), the Central American Technical Regulation countries, Brazil, Venezuela, Argentina, and Chile recognize the same common allergens as outlined by the UN/WHO Codex.
Additionally, Brazil requires labeling of products containing natural rubber/latex.
Europe
The European Union (EU) recognizes 14 common food allergens/intolerances—gluten-containing cereals, egg, milk, soy, peanut, tree nuts, fish, crustaceans, mollusks, celery, mustard, sesame, lupin, and sulfites.
Non-EU countries in the region that also follow these guidelines include Iceland, Liechtenstein, Norway, Macedonia, Switzerland, United Kingdom (UK), Belarus, Russia, Turkey, and Ukraine.
North America
In the United States, there are currently nine foods required for labeling as major food allergens—milk, eggs, peanuts, tree nuts, fish, sesame, shellfish, soy, and wheat.
Mexico and Canada recognize and require the labeling of allergens as outlined by the UN/WHO Codex.
Canada includes mustard and sesame on its list of top allergens.
Southwest Asia
The Gulf States Organization (GSO) recognizes the following allergens—gluten-containing cereals, egg, milk, soy, peanut, tree nuts, fish, crustaceans, mollusks, celery, mustard, sesame, lupin, and sulfites.
Of note, sesame is a very prevalent allergen in this region, and in Israel, studies have identified sesame as the second most common food allergen in children, after milk.
Southwest Pacific
Australia and New Zealand require labeling for common allergens as outlined by the UN/WHO Codex.
Additionally, Australia and New Zealand identify lupin, sesame, bee pollen, and royal jelly as common allergens.
Note that many common food allergens are also choking hazards (nuts, nut butters, shellfish, etc.), so be sure to learn how to modify these foods to make the consistency age-appropriate and safe for baby.
Next up: Symptoms of Allergic Reactions
Written by:
S. Bajowala, MD, FAAAAI. Board-Certified Allergist & Immunologist
V. Kalami, MNSP, RD, CSP, Board-Certified Pediatric Dietitian and Nutritionist
R. Ruiz, MD, FAAP. Board-Certified General Pediatrician & Pediatric Gastroenterologist
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