Food Allergies In Babies: Causes, Symptoms And Treatment

Feeding a baby is not like they show in an advert. They do not get used to eating solids as and when you begin feeding them. You do not immediately know what the baby likes and dislikes. And your worst fears can come true if the little one is allergic to any of the foods that you feed them.

Therefore, you must know the foods that have the potential to trigger a food allergy in an infant. In this article, MomJunction gives a complete picture about food allergies in babies and ways to manage and prevent the condition.

Why Does A Food Allergy Occur?

Food allergy happens when the body’s immune system mistakes food to be a pathogen and mounts a retaliatory immune response (1). It results in symptoms that are similar to a disease but are actually caused by the faulty response of the immune system.

The mistaken identity is the result of certain chemical reaction in the body. Let’s take a look at how this happens.

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What Causes Food Allergies In Babies?

Ingested food is processed by the stomach from where it moves to the small intestine. Here the food encounters the immune system’s cells present within the intestinal lining.

The food protein is incorrectly detected as a foreign substance (antigen), and the immune system releases a counter chemical (antibody).

A complex reaction between the antigen and antibody forms the chemical histamine, which reacts with the body tissue leading to visible external symptoms that we know as the food allergy (2).

Peanuts and eggs are two of the most common food allergens.

The immune system is more defensive against some foods than others.

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What Are The High Allergy Foods For Babies?

Certain foods are responsible for the most common allergies in infants. The US Center for Disease Control and Prevention (CDC) states that the following food groups account for 90% of mild to severe food allergic reactions:

  • Milk (from any animal source; breastmilk is safe)
  • Eggs
  • Fish
  • Crustacean shellfish (such as prawns and crabs)
  • Wheat
  • Soy
  • Peanuts
  • Tree nuts (such as walnut and hazelnut)

These are the top allergenic foods for babies while seeds such as sesame, mustard, and even chocolate are potential allergens. The baby is more susceptible to food allergies under certain conditions.

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What Are The Risk Factors For Food Allergy In Babies?

Yes, the chances of food allergy in the baby increase by several folds in the following situations (3):

  1. Family history of food allergies: The probability of food allergies is higher among infants, who have the problem in their family. The baby has a 40% chance of getting the allergy if one parent has it, and a 75% chance if both the parents have an allergy (4).
  1. Age of the baby: Food allergies affect about 8% of infants below 36 months, but only 3% of adults (5). It means younger infants are more prone to food allergies due to their underdeveloped immune system.
  1. Asthma: It usually increases the risk of food allergy, but the link between the two is not known. Experts believe that if asthma is triggered by an allergen (for example, accidentally inhaling particles of wheat flour), then the person may be allergic to its oral consumption (wheat allergy) too (6).
  1. Presence of other allergies: A baby with other allergic conditions, such as eczema, has an increased susceptibility to a food allergy.

Do note that the above conditions only increase the chances of food allergy. The baby may have the above issues yet be free of food allergy. Keep reading to learn all about the signs of food allergy in babies.

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What Are The Symptoms Of Food Allergy In Babies?

An infant with food allergy will display these signs:

  1. Skin hives: Red to pink rashes all over the body. The rash could be like a mosquito bite called welts or like a pinkish bump of skin called wheals. Rashes can be present all over the body but can be predominant on the face, back, neck, and legs.

Hives are often itchy and cause discomfort to the little one. They can last for hours depending on whether the baby is given medication or not. Even a mild food allergy can lead to hives.

  1. Swelling of parts of the face: Inflammation is observed on lips, nose, eyelids, and tongue. Fingers and toes may also swell. Swollen areas of the body may be extremely itchy.
  1. Runny discharge from the nose: A clear fluid would ooze out of the baby’s nose.
  1. Abdominal discomfort: It includes stomach cramps and sharp pain in the entire abdominal region.
  1. Vomiting and diarrhea: Diarrhea soon follows vomiting with the constant sensation of nausea.
  1. Lethargy and fussiness: The baby is less energetic, appears lethargic, and becomes fussy.

Unlike popular belief, constipation and fever are not the symptoms of food allergy (7). A food allergy may manifest within a few seconds or after several minutes but no later than two hours, depending on the intensity of the allergy. Severe food allergies in babies can lead to high-intensity symptoms. Such a state is called anaphylaxis, also known as anaphylactic shock. Following are the symptoms of anaphylaxis:

  • Tightening and narrowing of nasal respiratory tract
  • Swollen neck muscles that put pressure on the windpipe
  • Increase in heartbeat followed by sudden drop in blood pressure
  • Dizziness and partial unconsciousness
  • Blue coloration of skin and nails
  • Reddish or deep brown stools due to the presence of blood (8)

Blood-laden stools happen in severe cases of food allergy and when the baby suffers from other allergic conditions such as eczema. Anaphylaxis occurs in four out of ten cases of food allergies in infants (9). Take the infant to the doctor right away even at the slightest signs of food allergy.

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How Is Food Allergy In Babies Diagnosed?

The doctor will study the symptoms and learn more about the baby’s medical history. Parents will be asked about the usual diet of the infant in case the baby is older than six months. After considering the situation, the doctor will perform the following allergy tests on the baby (10):

  1. Blood test: A blood test will measure the quantity of antibody in the blood. The doctor will inquire about the baby’s diet in the past couple of hours and then assess the blood report to determine antibodies specific to the food item.
  1. Eliminating a food type: The doctor will ask parents to eliminate one suspected allergic food item from the baby’s diet per week. If a relapse of allergy is not noticed after discontinuing the food item, then it could be considered the reason behind the allergy.
  1. Skin prick test: It is the fastest and most accurate method of determining the cause of the allergy. A small, diluted quantity of a suspected allergen is injected into the upper layer of the skin. If the infant presents mild symptoms of the allergy, then it is concluded that the baby is allergic to that substance.

The above tests are usually conducted together to pinpoint the allergenic food item. Skin tests are safe and not a matter of concern. However, if the infant has repeated anaphylaxis or allergic conditions such as eczema and asthma then blood test and elimination of a food item are the only options because you cannot take the risk of aggravating the condition with a skin prick test.

A thorough conclusion helps the doctor suggest the best course of treatment.

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How Is Food Allergy In Babies Treated?

There is no definite baby food allergy treatment as there is no cure for food allergies (11). Tackling the symptoms helps provide relief, and there are only two ways of doing it:

  1. Antihistamine medication: Allergy symptoms are treated with the use of oral antihistamine medication that can be given at home after doctor’s consultation. The baby would also be prescribed an epinephrine auto-injector that the parents would have to carry with them all the time. Epinephrine shot is used in situations of anaphylaxis and can be administered by the parent immediately after the symptoms show up.
  1. Changes in diet: Avoiding the food substance that causes the allergy helps mitigate the problem.

Perhaps you have already guessed it that management of food allergy is crucial as there is no cure.

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How To Manage Food Allergies In Babies?

Managing your baby’s food allergy is simple and usually involves a few steps:

  • Choose hypoallergenic baby food: A hypoallergenic formula is recommended by the pediatrician when the baby is allergic to cow’s milk and relies only on formula for nourishment. Babies with cows milk allergy are usually allergic to soy as well, and thus cannot be given soy formula. Hypoallergenic formula is the only choice as it is made from hydrolyzed proteins, which are simpler amino acids that do not trigger allergic reactions (12).
  • Avoiding food items with allergen derivatives: A cracker could contain soy flour while a pudding may contain egg. Allergens could be hiding in any food and parents should double check the ingredients before feeding it to the baby. Such prudence is necessary for older infants that can eat a variety of solid foods including foods such as crackers and pudding.
  • Check vaccines before immunization: Most vaccines are safe for the baby, but a few such as influenza (flu) and yellow fever vaccines are derived from egg proteins – a common allergen (13). Yellow fever is not part of the usual immunization schedule of the baby, but influenza is widely recommended. Parents must discuss with the doctor about flu vaccine before going ahead with the vaccination. A non-egg protein version of the vaccine can be used. It could be expensive, but completely safe for the baby with egg allergy.

When managed correctly, allergies pose no hindrance to the baby’s healthy growth and development. You can reduce the chances of food allergy in babies.

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How To Prevent Food Allergies In Babies?

There is no definite way of preventing food allergies since they happen spontaneously. Nevertheless, you can try the below:

  1. Introduce allergen foods after one year: Foods that commonly cause allergy (mentioned earlier) should be introduced after the baby is 12 months old. You must wait till the baby is 24 months, that is two years, before introducing crustacean shellfish (prawns, crabs, and lobsters), nuts, and seeds (14). Adding allergen foods to a baby’s diet later reduces the chances of allergy outbreaks since the immune system would be more robust.
  1. Have a gradual increase in the quantity: When it is the time to let the baby eat such food, do not go straight to full servings. Instead, start with small quantities. For example, when introducing eggs, start by giving the baby a couple of scrambled egg pieces every day. Gradually increase the quantity over a few days. A controlled introduction helps gradually desensitize the baby’s immune system to an allergenic food.

Lactating mothers need not stay away from common allergenic foods to prevent allergies. If the baby has a confirmed food allergy, then the mother can avoid eating the allergenic food. However, it seldom has any effect, and in most cases, mothers can consume the allergen without it having any impact on the infant with allergy (15).

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Frequently Asked Questions:

1. Can babies be allergic to breastmilk?

No. Breastmilk is tailor-made to suit the infant’s immune system and thus unlikely to trigger an allergic reaction (16). If you observe signs of food allergy in the breastfed baby and he is not on solid foods yet, then it could be a case of congenital lactose intolerance or galactosemia. Both conditions cause intolerance towards breastmilk sugars leading to abdominal discomfort (17) (18). However, these are not allergies, but intolerances, i.e., body’s inability to produce the necessary digestive enzymes to break down molecules of milk sugars.

2. Is food protein-induced enterocolitis syndrome a food allergy?

Yes, food protein-induced enterocolitis syndrome (FPIES) is a type of food allergy. It is triggered by soy, milk, cereal grains, fish, and shellfish meat. Unlike standard food allergies, it is not caused by nuts and seeds, but less allergenic foods such as rice, oats, and chicken meat (19). The symptoms, prognosis, and management of the condition are the same as those of a regular food allergy.

3. Can babies outgrow food allergies?

Yes. A study in the US has found that about 26.6% of infants with food allergies eventually outgrew it after the age of five-and-a-half years (20). The majority continued with a persistent food allergy. However, allergies can get limited to some foods when the baby grows older. For instance, allergies to milk, eggs, soy, and wheat can resolve after the age of five. But allergies to fish, shellfish, peanuts, and tree nuts stay for a lifetime (21).

4. What is the difference between food intolerance and food allergy?

Food intolerance is the gastrointestinal tract’s inability to break down the molecules of a food substance (22). It usually causes abdominal discomfort with symptoms such as stomach pain and diarrhea. The difference between food allergy and food intolerance is:

Food AllergyFood Intolerance
Immune system’s response to food substanceInability of gastrointestinal tract to digest a food substance
Quick onset of symptomsSlower onset of symptoms compared to food allergy
Caused by faulty immune systemCaused by absence of certain digestive enzymes
Allergy symptoms include abdominal discomfortOnly displays abdominal discomfort
Anaphylactic allergic reaction is life-threateningMay cause severe discomfort, but never life-threatening

Unlike a food allergy, food intolerances do not involve the immune system, and are also called food sensitivity and non-allergic hypersensitivity (23). Example of a food intolerance is lactose intolerance, which is different from a milk allergy. Food intolerance is more common yet less severe than food allergies.

5. Does the order of introducing solid food influence the chances of allergy?

Yes. Once the baby turns six months old, all solid foods should not be introduced at once. Instead, they should be offered gradually as the baby grows. This ensures that you are able to gauge which food has caused the allergy. Here is a table that gives the correct sequence of offering solid food to a baby:

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Food allergies can be managed easily. You can even keep a logbook to note down when and how symptoms showed up. Breastmilk is the safest food for babies till six months, and thereafter you could introduce solid foods gradually.

If you have any tips on managing food allergies in babies, share them with us in the comments section below.

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Rohit Garoo

Rohit Garoo took writing as a profession right after finishing his MBA in Marketing. Earlier he graduated with a Bachelor’s degree in Botany & Zoology from the autonomous St. Xavier’s College in Mumbai. Rohit has also done a Stanford University certification course on breastfeeding. This botanist-zoologist turned writer excels at life sciences, and at MomJunction he writes everything about pediatrics and maternal care. In between writing and being overly curious, he spends time cooking, reading, and playing video games. LinkedIn profile –
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