Allergies and Sensitivities 101

It is so common to hear someone say “my child has allergies” when in fact they are often sensitivities or intolerances.

It is estimated that 1 in 3 children (or more) has food intolerances (are sensitive to particular foods) and 1 in 17 children has a life threatening food allergy.

So what is the difference?

True Allergies

True allergies, in most cases, are specific adverse reactions to an allergen (a substance that causes an allergic reaction) that trigger the production of an antibody, immunoglobulin E–IgE.

Allergies always have an immediate response time and trigger a histamine reaction.

When the antibody (IgE) binds to basophils and mast cells (white blood cells) it triggers the release of histamine.

Histamine is an important chemical in the body and an excessive release of histamine from basophils, mast cells and eosinophils can result in a wide range of symptoms including:

  • Rashes
  • Hives
  • Swelling
  • Closing up of the airways
  • Sneezing
  • Even a more dangerous reaction of the immune system called anaphylactic shock

Children with anaphylaxis may die within minutes if they consume even small particles of the food to which they are allergic.

Common foods found to be triggers of allergic reactions are:

  • Peanuts
  • Corn
  • Shellfish
  • Nuts
  • Food additives
  • Eggs
  • Soy
  • Gluten
  • Casein
  • Fish
  • Sulfites in foods

Allergies can be reactions to foods, chemicals, the environment, toxins and pathogens.

Allergies have been known to adversely affect mood and behaviors in children as well as the central nervous system.

Many children with autism, ADHD, Sensory Processing Disorder, learning disabilities, asthma, autoimmune disorders and mood disorders have been found to have allergies as well as sensitivities.


Sensitivities often involve a delayed onset of symptoms to foods, chemical preservatives, toxicity and/or a variety of pathogens which may take up to several hours, or even days, to appear.

Very often food sensitivities in children go undiagnosed or misdiagnosed because delayed reactions can be hard to detect.

Food and environmental sensitivities are characterized by an inflammatory response but are not detectable with a typical IgE test (the test used to diagnose “true allergies”).

Thus, many physicians overlook allergies and sensitivities if they only give their patients an “IgE test” such as a skin scratch test or a RAST blood test.

It is important for parents to ask their physicians to test for food sensitivities/intolerances to get a full picture of what else (besides ‘true allergies’) might be causing inflammation in their child’s body.

Scientists are now linking food and environmental sensitivities to conditions as varied as autoimmune conditions, irritable bowel syndrome, schizophrenia and depression.

Wheat, in particular, has been identified as a common food sensitivity that can contribute to a whole host of chronic inflammatory conditions.

This phenomenon is so common that researchers have now identified a significant portion of the population that has non-celiac gluten sensitivity and who benefit greatly from a wheat/gluten-free diet.

Typically, when someone has allergies and sensitivities they also have a compromised gut lining and a condition known as “leaky gut syndrome“.

This is when the lining of the intestines becomes excessively permeable (hyperpermeability) and then underdigested food, toxins, and microbes may pass through the lining of the gut and end up in the blood stream triggering a reaction and causing chronic systemic inflammation.

The results of chronic systemic inflammation can be subtle and can include:

Sensitivities can also trigger:

Antibiotic Usage

Frequent antibiotic usage may contribute to an increased risk of allergies and sensitivities during childhood.

Research has shown that children who receive one or more doses of antibiotics before the age of two have much higher incidences of asthma, eczema and hay fever; in fact, the more doses of antibiotics a child received, the higher their risk of having one or more of these conditions.

Antibiotics disrupt the good bacteria in the microbiome and the microorganisms in the gastrointestinal system which can in turn alter immune function.

Antibiotics can lead to yeast overgrowth (such as species of Candida) which can increase allergies and sensitivities and compromise immune function.

What can be seen in certain children is that allergies and sensitivities affect the immune system, the gut/brain connection and brain functioning, children’s behavior and immune responses.

Is This Your Child?

Doris Rapp, MD is one of the very first doctors who recognized certain symptoms in children as possible allergy or sensitivity reactions.

In her groundbreaking, informative book, Is This Your Child?, she described what parents of children on the autism spectrum (who usually have many sensitivities) often see in their children:

She also identified many behaviors, problems and conditions that are prevalent with allergies and sensitivities:

When parents remove the inflammatory culprits, often times there will be improvement in focus and concentration, language, cognitive, behavior and general well-being and mood.

In the case of food sensitivities, food rotation is a good option to avoid developing further food sensitivities if your child eats the same type of foods on a regular basis.

The table below shows the differences between the two different types of immune-mediated adverse food reactions: food allergies and food sensitivities.

Food Sensitivities Food Allergies
Body Organs Involved Any organ system in the body can be affected Usually limited to airways, skin or gastrointestinal tract
Symptom Onset Occurs From 45 minutes to 72 hours after ingestion From seconds to one hour after ingestion
Are symptoms acute or chronic? Usually chronic, sometimes acute Usually acute, rarely chronic
Percentage of population affected 20-30 percent 1-2 percent
Immunologic Mechanisms White blood cells, antibodies: IgA, IgC (and subclasses), IgM, C3, C4 IgE
Non-immunologic Mechanisms Toxic, pharmacologic None
How much food is needed to trigger reaction From small amount to large amount, often dosage-dependent One molecule of allergic food needed to trigger reaction


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Feingold, Ben, MD. Why Your Child Is Hyperactive: The Bestselling Book on How ADHD Is Caused by Artificial Food Flavors and Colors. Random House, 1985.

Rapp, Doris, MD. Is This Your Child? William Morrow Paperbacks, 1991.