Food Allergies in Children

The Centers for Disease Control and Prevention (CDC) released a study in 2013, citing that food allergies among children increased approximately 50 percent between 1997 and 2011. Below, we address some common questions and topics related to food allergies in children.

At what age do children typically develop symptoms of a food allergy?

Food allergy symptoms can start as early as birth (ex: cow milk protein allergy, eczema), or they can present much later into adolescence.

IgE-mediated vs. Cell Mediated Food Allergies

IgE-mediated food allergies cause your child’s immune system to react abnormally when exposed to one or more specific foods such as: milk, egg, wheat or nuts. Children with this type of food allergy will react quickly — within a few minutes to a few hours. Immediate reactions are caused by an allergen-specific immunoglobulin E (IgE) antibody that floats around in the blood stream [source].

IgE mediated food allergies can occur early (ex: cow milk allergy), or it can require multiple exposures before symptoms occur (ex: peanut allergy). Cell mediated allergies  usually present later, except in severe cases. Cell mediated allergies may have more vague symptoms that take longer to identify an allergy component (ex: Celiac, Eosinophilic esophagitis (EoE)).

Common Food Allergies in Children

The most common food allergies in children include:

• Milk
• Soy
• Egg
• Wheat
• Peanut
• Tree nut
• Fish
• Shellfish

It’s important to note that the protein fraction is the allergenic portion. Most highly processed oils are considered low risk by the Food Allergy and Anaphylaxis Network (FAAN), but it should be discussed with your allergist.

Is there anything that predisposes a child to develop a food allergy?

Family history can predict some food allergies – especially if it is a parent or sibling. Family history can include: hay fever, eczema, food allergies or asthma.

At what age should parents introduce nuts, and other foods notorious for allergic reactions?

There is no consensus on this topic. Previously we were told to hold any nut products until 2-3 years of age. However, a study out of Israel using peanuts has led us to believe that very early introduction can be protective of food allergy as the immune system will be less likely to view that protein as an allergen if it is present very early.

More importantly, we need to make sure foods are age appropriate. For example, nuts and nut butter are choking hazards for children under 3 years of age. If there is a family history of severe nut allergy, you should defer to your child’s doctor or family allergist.

Eggs are now considered ok to introduce earlier. Most children will outgrow allergies by the time they are 5 years old.

What are some common myths surrounding food allergies in kids?

One of the biggest myths surrounding food allergies in children is that parents are exaggerating the allergy. Some food allergies are not visible – such as in the case of Eosinophilia disorders. You don’t have to stop breathing to have an adverse reaction to food!

Signs that a Food Allergy is Serious

Signs of a serious allergic reaction to food include:

• Lip or facial swelling
• Feeling unable to catch one’s breath
• Vomiting
• Profuse diarrhea
• Tingling or itching of the lips, mouth and throat

All of these reactions should be treated as an emergency, and they should be evaluated by a doctor.

Testing for Food Allergies in Children/Infants

Food allergies can be tested by skin testing or a radioallergosorbent (RAST) test that is done in a pediatrician or allergist’s office. These are IgE mediated allergies.

In some children, a food challenge will be done in a doctor’s office to diagnose or see if allergy has been outgrown. The child will eliminate the food, but then consume it shortly before coming to office or while in the office.

Other allergies that are mixed or cell mediated may be evaluated by endoscopy or elimination diets to see if symptoms improve. Skin testing can be done at any age. There may be some false positives if the child has an inflammatory condition such as eczema.

Some allergies, such as Celiac disease or EoE cannot be detected with a skin test and require endoscopy +/- blood tests. Blood tests are not always reliable.

Preventing the development of food allergies in Infants

Exclusive breastfeeding (defined as no food or liquids other than human milk) for 4-6 months is protective against food allergies.

Also, no pureed/solid food introduction before 4 months, but not after 7 months of age may prevent food allergies from developing. The gut may have a “sweet spot” when the gut is ready to start processing different proteins.

About Shelley B. Wilkins, MS, MPH, RD

Shelley is a Pediatric Dietitian and Lactation Consultant with WakeMed.