Food allergy symptoms

What is a food allergy?

A food allergy occurs when the immune system reacts to specific proteins found in food, resulting in skin, gastrointestinal, cardiovascular, or respiratory symptoms. The majority of food allergies are triggered by nine allergenic foods, which are:

Cow’s milk

• yogurt
• butter
• cheese

Wheat

• Wheat-based infant cereal
• Bread 
• Couscous
• Pasta

Egg

• Baked goods with egg
• Scrambled eggs
• Omelette
  
  

Soy

• Edamame 
• Tofu
• Soy milk/formula
  
  

Sesame

• Tahini 
• Sesame seeds 
• Hummus with tahini
  
  

Tree nuts

• Almonds
• Cashews
• Walnuts
• Macadamia nuts
• Pistachios 
• Pecans
  
  

Peanuts or peanut butter

Fish

• Salmon
• Trout
• Halibut
• Tuna
  
  

Shellfish

• Shrimp
• Lobster
• Crab
  
  

We recommend introducing food allergens when your baby is 6 months old, around the same time they begin eating solid food. Recent research suggests that introducing allergenic foods early and regularly, can significantly decrease the risk of developing a food allergy. 

 Allergic reactions can occur immediately after exposure or hours later. When introducing allergens, we suggest offering them early in the morning, so you have a whole day to monitor for signs and symptoms.

Symptoms

Allergic reactions can vary, and may appear differently in each child. Symptoms can range from mild and manageable to severe and potentially life-threatening. Also, reactions may appear differently each time. A food that triggers a mild reaction on one occasion might lead to a more severe one the next time. Symptoms of an allergic reaction may include:

• Swelling
• Itching
• Hives
• A severe rash
• Gastrointestinal discomfort, stomach pains
• Nausea
• Vomiting
• Diarrhea
• Persistent coughing
• Itching or tightness in the throat
• Low blood pressure, dizziness
• Shortness of breath
• Wheezing
• Anaphylaxis
  
  

Swelling

Swelling is a food allergy symptom and usually occurs around the face, lips, mouth, or eyes. If there is swelling around the mouth or, it could potentially cause breathing difficulties, and requires immediate medical attention.

Hives

Hives are different from regular rashes because you’ll notice raised, red, or pink welts or bumps on the skin's surface. Hives can also appear in patches and are usually itchy. Rashes can vanish within 24 hours, whereas hives may last for a few days.  

Wheezing 

According to the American College of Allergy, Asthma, and Immunology, wheezing sounds like whistling or squeaky sounds in your chest when you breathe. It can happen when the throat or airway is inflamed or restricted. Wheezing can be a symptom of an allergic reaction. 

Anaphylaxis

Anaphylaxis is the most severe, life-threatening allergic reaction, marked by difficulty breathing, a significant drop in blood pressure, and changes in heart rate. Symptoms and severity may vary, and can be unpredictable too. Anaphylaxis can occur within minutes or hours of exposure to the allergen. Immediate medical treatment is crucial, typically involving an epinephrine injection. If you suspect your child is having a severe reaction and breathing is inhibited, call 911 or emergency services immediately. Make sure to follow up with your child's pediatrician too.

FPIES

Food protein-induced enterocolitis (FPIES) is a type of food allergy that primarily affects infants and young children. Symptoms of FPIES include severe vomiting, diarrhea, and dehydration, typically occurring several hours after consuming the trigger food. Common foods that can trigger FPIES include cow’s milk, soy, rice, barley, oats, chicken, turkey, and fish. Fortunately, FPIES usually resolves by age four.

FAQ: Allergies in children 

Here are some common questions regarding babies and food allergies:

When should I take my child to the ER for an allergic reaction?

If you suspect your child is experiencing a severe allergic reaction, such as difficulty breathing or anaphylaxis, it is important to seek immediate medical attention. Call 911 and request an ambulance, or take your child to the nearest emergency room. Be sure to follow up with your child's pediatrician after any emergency visit. 

How should my baby be tested for a food allergy?

If you suspect your child has a food allergy, make an appointment with your child’s pediatrician or allergist. Your healthcare provider may ask for a detailed history, including food logs and symptoms. Be sure you keep track of symptoms, their duration, and the amount of food consumed. Following a comprehensive evaluation, your doctor may conduct a skin-prick test, blood test, or oral food challenge to establish a diagnosis.

• During a skin-prick test, your healthcare provider will use a small needle to prick the skin on your baby's back with a liquid containing the food allergen. They will also prick the skin with a control that does not contain any food allergens to compare reactions. While typically not painful, this test can be uncomfortable for a baby as they need to remain still without lying on their back or applying pressure to it for about 20 minutes. After the test, your healthcare provider will examine your baby's back to check for any reactions. A bump at the site of the skin prick indicates a reaction.
  
  
• Blood tests will measure the presence of antibodies, indicating the immune system's response to that particular food allergen.
  
  
• An oral food challenge involves giving your baby the suspected food allergen and closely monitoring their reaction. The challenge is conducted under strict medical supervision.
  
  

How do I know if my baby has food sensitivity or intolerance?

Unlike an immune response with food allergies, a food sensitivity or intolerance occurs when a baby has difficulty digesting specific foods. Symptoms are strictly gastrointestinal and may include abdominal pain or discomfort, excess gas, vomiting, or diarrhea. 

Babies have developing digestive systems, and for some, breaking down large proteins like those found in milk or soy can be challenging. One common example is Milk Soy Protein Intolerance (MSPI), a food intolerance where babies have difficulty digesting dairy and soy products. Fortunately, MSPI is usually temporary and tends to resolve as the baby's digestive system matures, usually by their first birthday.

What are 90% of food allergies caused by?

90% of food allergies are caused by the nine major food allergens: cow’s milk, wheat, egg, soy, sesame, tree nuts, peanuts, fish, and shellfish.

How should I prepare allergens?

Here are a few examples of how to introduce food allergens, either in puree form or as finger foods:

• Cow’s milk: a couple spoonfuls of plain yogurt, mix cow’s milk or melted butter into a prepared dish
  
  
• Wheat: wheat based infant cereals, lightly toasted bread
  
  
• Egg: pureed hard-boiled eggs, scrambled eggs, omelet
  
  
• Soy: pureed edamame, soft tofu strips
  
  
• Sesame: thinned tahini mixed in yogurt or infant cereal, sesame seeds
  
  
• Tree nuts: powdered almond butter or thinned cashew butter mixed in oatmeal or applesauce
•  Peanuts: thinned peanut butter mixed in yogurt or oatmeal
  
  

• Fish: pureed cooked salmon, flaky pieces of salmon
  
  
• Shellfish: pureed cooked shrimp
  
  

Who is most susceptible to developing a food allergy?

It is important to know if your baby has an increased risk for developing a food allergy before introducing them. Children with severe eczema or with another known food allergy have a higher risk of developing food allergies. 

Are peanut allergies the most common allergies in children?

A peanut allergy is one of the most common food allergies in children. It can cause severe allergic reactions. If your child has a peanut allergy, it does not necessarily mean they have a tree nut allergy. For further guidance, reach out to your child's allergist. 

If my baby is allergic to one tree nut, should I assume all tree nuts are a no-go? 

Not necessarily. If your baby is allergic to almonds, for example, it doesn’t necessarily rule out cashews or pine nuts. Always consult your child’s allergist when navigating food allergies.

How do I know if my baby has a milk allergy?

Symptoms of a milk allergy can manifest as hives, gastrointestinal discomfort, vomiting, bloody stools, or even anaphylaxis. If you suspect your infant has a milk allergy, it's essential to consult with your child's pediatrician or allergist. They can advise on switching to an alternative formula or eliminating dairy from the mother's diet if breastfeeding.

Should I have an epinephrine auto injector?

If your child has a food allergy, it’s important to have epinephrine auto injectors with you at all times. Epinephrine, also known as adrenaline, is a hormone that can elevate blood pressure and open airways, potentially saving a life during an allergic reaction. Make sure to keep epinephrine auto injectors at home, at daycare, in your diaper bag, or in your car. 

References:

NCBI: Food Allergies. 

NCBI: Food allergy in children—the current status and the way forward.

American College of Allergy, Asthma, and Immunology: Wheezing, shortness of breath

American College of Allergy, Asthma, and Immunology: Food Protein-Induced Enterocolitis Syndrome (FPIES)

‍