How Do You Know If Your Baby Has a Food Allergy?


Introducing your baby to her first solid food around the sixth month or so is one of the most exciting milestones for you and your baby. But how do you know if your baby has a food allergy if you’re not acquainted with the symptoms?

Babies cry for many reasons because that's their only way of interacting with the world around them. Babies often cry when they're hungry, tired, and need a nap or a diaper change. 

But, babies may also cry when they experience some of the discomforts related to a food allergy. Interestingly, the American Academy of Paediatrics (AAP), in their 2018 study, found that approximately 8 per cent of children in the U.S. suffer from a food allergy. It shows an increase of 3% from a study done ten years earlier. 

Unfortunately, food allergies in babies can be challenging to identify if you don't know what the symptoms are and how to recognize them. In this article, we will take a closer look at the signs, symptoms, causes, severity, offending foods, and treatment of babies’ food allergies.

Happy Boy Without Allergies

The causes of food allergies in babies

If your family has a history of food allergies and related conditions, the chances of your baby having allergies increase. Although this is not always an accurate indicator of the type of allergy your baby will develop. 

Our body’s immune system is always on the warpath, effectively intercepting and eliminating infections, various threats, and dangers to our good health. 

However, with a food allergy, the body over-zealously identifies a particular food or substance as an ‘invader’ – a potential danger to your body’s health – and goes over into protective mode, trying to defend the body by releasing histamine to neutralize the threat. 

In more severe allergic reactions such as anaphylaxis, the body's immune system releases large amounts of histamine and a cocktail of chemicals and other substances into the blood immediately after ingesting a trigger food

The symptoms can be frightening as this allergic reaction impairs breathing, lowers blood pressure, and affects the heart rate. It quickly becomes potentially life-threatening and requires prompt medical treatment. (more on how to treat anaphylaxis later in this article).

Unless an allergic reaction occurs within the first hour or two after a feed, you may not know if your baby has a food allergy. 

Delayed allergic reactions such as eczema appear within four to six hours – even days – after feeding your baby a specific food. You may not necessarily regard it as an allergic reaction or even relate the condition to food. 

Signs and symptoms of mild to moderate food allergies in babies 

If, after introducing your baby to a new food, you notice unusual squirming, moaning, skin discolouration, stomach discomfort, and vomiting, these may be signs that a food allergy causes it.
Yes, we know that babies often spit up, drool, and cry for various reasons that do not require medical treatment. But because babies don’t have the verbal skills to communicate their discomforts. You need to watch out for certain signs and mannerisms that will indicate that your baby has a food allergy and requires medical treatment.

Your baby may experience one or a few mild to moderate allergic reactions occurring at the same time. 

  • Irritating itchiness and tingling of the throat and mouth
  • Swelling of the eyes, lips, or face 
  • Hives, welts, or a rash on the baby’s body or face
  • Eczema (after a few hours or days)
  • Vomiting and signs of abdominal discomfort 
  • Congestion, runny nose, and sneezing 
  • Diarrhea

Watch your baby's movements to ascertain where the discomfort is:

  • May scratch or start pulling at their tongue
  • Put their little hands in their mouth 
  • Pulling up their legs anxiously
  • Baby’s voice is hoarse or squeaky 
  • May start pulling at their ears
  • Crying, moaning, and unusual behaviour

Eczema and its link to food allergies

Eczema is one of several atopic conditions in which a hypersensitive reaction occurs. This is caused by allergen exposure on a different part of the body.  It may appear as an itchy rash that can become scaly, red, and in extreme cases, raw. 

  • In babies from 0 to 6 months, eczema appears typically on the cheeks, chin, forehead, and scalp. Initially, it may look like red bumps and ooze fluid. It could also spread to other areas of the baby's body.
  • From 6 to 12 months, it is often located on the baby's knees and elbows. This is due to the skin in these areas constantly in contact with the floor surface during crawling. If a rash becomes infected, it may form a yellowish crust.

According to a 2017 review published in The Lancet, it appears that eczema precedes the development of food and other allergies. 

It is now hypothesized that eczema prepares the body for allergies by lowering the function of the skin’s ability to act as a barrier.

How to know if your baby’s allergic reaction to food is severe

Identifying a severe food allergy – anaphylaxis- in your baby may come with challenges. This is due to some of the key symptoms being similar to mild and moderate allergic reactions. Vomiting, drooling, diarrhea, itching, scratching, drowsiness are all features of common signs that your baby has a food allergy.

  • The critical difference between a mild, moderate, and severe allergic reaction is that a severe reaction will occur quickly. Usually between 5 to 30 minutes after your baby has consumed a particular food.
  • A scientific study conducted with 357 children ranging from infants to school-going age found that vomiting, hives, and gastrointestinal symptoms had the highest presence in cases of severe allergic reactions to food.
  • Identifying the signs and symptoms of an allergy is crucial to having your baby effectively diagnosed and treated by a health practitioner.

Any of the following severe symptoms may be an indication of anaphylaxis.

  • Vomiting, stomach cramps
  • Laboured and/or noisy breathing
  • Wheezing and/or persistent hoarse cough
  • Swelling of the tongue or lips
  • Swelling and/or tightness in the throat
  • Slurred speech (baby syllables), or hoarse voice
  • Dizziness, and the baby becomes floppy 
  • Pale or blue skin colouring

NB: stomach pain and vomiting alone are signs of anaphylaxis caused by an insect sting.

Call the relevant emergency medical line for an ambulance. It’s always safer to ‘err on the side of caution.’

Common foods that cause allergic reactions in babies

While most allergic reactions when they occur are typically mild, when you're introducing your baby to a new food, it's essential to be alert for any allergic symptoms and reactions indicating that your baby has a food allergy.

  • Eggs: If your baby experiences discomforts such as pain in their tummy, a rash, or any other abnormal reactions after eating a meal containing eggs, it may mean that their body’s immune system is overreacting to the proteins in the egg white, the yolk, or both. 

Medical experts have estimated up to 2 percent of babies and children have an allergic reaction to eggs, but fortunately, 70 percent outgrow it by age sixteen. 

Symptoms of an allergic reaction to eggs may include some of the symptoms for mild to moderate allergic reactions. Anaphylaxis is less common in egg allergies.

  • Milk and Dairy – Milk is excellent for building bone strength, but unfortunately, it's also a typical food allergen. According to ACAAI, between 2 to 3 percent of kids under the age of three years are allergic to cow's milk.

Some babies may outgrow it during their toddler years. Studies have shown that up to 80 per cent outgrow this allergy by the time they reach 16 years. 

Symptoms that your baby is allergic to milk include vomiting, pain or upset tummy, and bloody stools. In rare cases, anaphylaxis may occur.

  • Peanuts: This legume (no, it’s not a nut) is the most’ famous’ and common cause of allergies among children leading to anaphylaxis. Many U.S. schools have declared their school grounds ‘nut-free'. This means no peanut butter and jelly sandwiches in the kids’ lunchboxes. 

Symptoms indicating that your baby has an allergy to peanuts may include some of the severe allergic reactions related to anaphylaxis.

  • Tree nuts:  Walnuts, Almonds, and Brazil nuts are also linked to anaphylaxis. 25 – 40 percent of people who have an allergic reaction to peanuts are also allergic to one or more nuts. A nut allergy is seldom outgrown. 

Symptoms may include some of the severe allergic reactions related to anaphylaxis.

  • Fish: An allergic reaction to canned fish such as halibut, tuna, or salmon, can lead to anaphylaxis which requires emergency medical treatment. 

Symptoms of fish allergies in babies are mostly experienced as mild to moderate allergic reactions. Anaphylaxis is less common in fish allergies. 

  • Shellfish: Close to seven million Americans are affected by shellfish allergies, regarded as one of the most common food allergens. Individuals who are allergic to shellfish, such as crab, lobster, etc., may not necessarily be allergic to other fish.

Symptoms of a shellfish allergy may include severe allergic reactions related to anaphylaxis.

  • Wheat allergies are more prevalent in babies born to parents with a history of allergic conditions such as asthma or eczema. Most babies can eat wheat products such as bread and confectioneries without experiencing any problems.

Symptoms of wheat allergies in babies may include mild to moderate allergic reactions. Anaphylaxis is less common in wheat allergies.

  • Soy: This is a member of the legume family and a popular ingredient in infant formulas and various processed foods. However, it has been found as a regular culprit of food allergies in babies and children. According to studies, children outgrow this allergy as they grow older.

Symptoms that your baby is allergic to soy may include some of the mild to moderate allergic reactions. Anaphylaxis is rarely experienced in soy allergic reactions.

The Centre for Disease Control and Prevention (CDC) states that children with food allergies have a two to four times higher probability of developing allergic conditions such as asthma. Unless babies outgrow allergies when they're older, it can't be cured, only the offending foods avoided, according to medical experts. 

How to safely introduce your baby to common food allergens

It may sound scary, but according to trusted sources; The American Academy of Pediatrics and a study published in the 2018 Journal of Allergy and Clinical Immunology: In Practice, parents should introduce potential allergens to their babies early. 

They recommend introducing your baby to peanuts (peanut butter) as early as from 4 to 6 months old to prevent them from developing an allergic reaction to peanuts and other allergens at a later stage. 

This reverses the previous policy to introduce allergens to babies when they're a bit older. Their bodies are better equipped to manage the possible allergic reactions.

The experts maintain that if your baby is at high risk, i.e. has severe eczema or an allergic reaction to eggs, or both; you can be sure that other allergies will develop.

To prevent a milk allergy, mothers should breastfeed their baby for the first 4 to 6 months due to the higher nutritional value of breastmilk and infant formula. 

According to the medical experts, the other food that could cause allergic reactions, such as tree nuts and fish, should be introduced along with the other solid foods, between 6 to 9 months. 

Pediatric experts emphasize the importance of introducing your baby to one food at a time. Then wait three to five days before introducing the next one. This is to isolate an offending food when an allergy occurs. The allergy can then be traced to the exact food causing the allergic reaction. 

Wait until the baby is at least one year old (some medical experts prefer two years old) before introducing honey. This caution is due to an allergic reaction to honey linked to a severe condition called infant botulism.  

How you can safely relieve your baby’s allergy symptoms

According to The Royal children’s Hospital in Melbourne,  most children with mild to moderate symptoms of food allergies should respond well when given oral antihistamine medication. Talk to your baby’s pediatrician about carrying antihistamine medicines with you. It’s best to obtain antihistamines that don’t lead to drowsiness.

For severe allergic reactions, your pediatrician will give you a prescription for a pre-filled syringe with epinephrine.  Epinephrine is a hormone that effectively reverses the severity of anaphylaxis to improve breathing and stabilize blood pressure. 

Most importantly, ensure that trusted family, partners, and carers know where you store the autoinjector and that they are knowledgeable about its use. Take the little one immediately to the emergency room afterwards as the allergic symptoms may return.

 If your little one has a history of anaphylaxis, your pediatrician will prescribe an adrenaline autoinjector. If you don’t have access to an autoinjector, call an ambulance immediately.  

How you can prevent food allergies in your baby

It may sound simple enough ‘to avoid the offending food‘. But in packaged foods, ingredients can be hidden, such as peanuts and other nuts, dairy, wheat, etc. It is essential to check labels and know every name by which an offending food is known.  

Most countries have laws on how manufacturers of packaged foods should use simple, straightforward language to identify any of the eight primary food allergens in products. Even if a product contains only a minuscule amount as an additive or flavouring, it must be noted on the label.

In cases where cross-contamination is a threat, the label should state clearly, “made on shared equipment”, “might contain”, “made in a shared facility”, “may contain” etc.

If your baby has several food allergies, you may prefer to prepare your baby's food at home. This way, you will know the exact ingredients your baby is consuming. 

The bottom line

Your baby's doctor can assist you with getting the appropriate allergy testing for your baby and prepare you for those incidents of severe allergic reactions. This way you’ll know how to stabilize and calm your baby in an emergency.

When you go out, make sure to keep safe foods, especially for toddlers. Become a food label guru as you inspect every food label for ‘hidden’ allergens not listed on the label or mentioned by another name.

Yes, it can be scary not knowing if your baby has a food allergy and having to hold your breath every time you introduce a new food. Parents need to be well-prepared to recognize the signs and specific symptoms to differentiate between mild, moderate, and severe allergic reactions and how to manage and safely treat them. 


What is the difference between an allergy and food intolerance? 

An allergy is an abnormal, ‘over the top’ immune response to a normally harmless food. The immune system attacks it by producing histamine (an inflammatory chemical) to neutralize what it perceives as a threat to the body. The histamine causes itchiness and swelling


On the other hand, food intolerance has to do with the digestive system and not the immune system. It usually occurs when the body is deficient in the digestive enzymes required for breaking down an ingredient in certain foods. This is the primary cause of gas, bloating, and stomach cramps. Lactose intolerance (milk) and gluten (in wheat) are more commonly known.

Sometimes the symptoms can overlap. It’s advisable to consult a pediatric allergist who can do a blood or Skin-prick test to make an accurate diagnosis. 

Does breastmilk contain allergens?

The Mayo Clinic asserts that certain foods and drinks in a breastfeeding mom's diet could cause an allergic reaction such as irritability, diarrhea, or wheeze in your baby after a nursing session. They advise consulting your baby’s doctor in such cases. 

However, the medical experts emphasize adhering to a well-balanced, healthy diet and eliminating cabbage, garlic, and onions to see if it helps. They also advise limiting the consumption of coffee to no more than 3 cups per day. And avoiding fish with high mercury content and alcohol while breastfeeding.  

It’s all about making healthy choices and checking in with your baby's pediatrician if you’re unsure about anything.

Even in this high-tech age, the low-tech plant continues to be the key to nutrition and health

– Jack Weatherford

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