Food Sensitivities and Allergies

Rationale: Many children with autism have food sensitivities, due to abnormalities in their
digestive and/or immune systems. If food is not fully digested into individual sugars, amino acids,
etc., then the partly digested food can cause the immune system in the gut to react to those foods.
This reaction is much more likely to occur if there is inflammation of the gut.

Immune reactions can involve an immediate allergic reaction (mediated by IgE antibodies), or
they can be delayed by several hours to 1-2 days due to other parts of the immune system being
involved (so-called non-IgE mediated food allergy).

Immediate-type responses can range from mild to severe, and may involve hives, respiratory
problems such as choking/wheezing, diarrhea, vomiting, dizziness/feeling faint, or even severe
reactions such as anaphylaxis.

For delayed-type food allergy, symptoms are typically limited to GI tract, but may involve
headaches, migraines, or other reactions. For example, some patients with celiac disease (immune
reaction to wheat mediated by IgA antibodies) may develop migraines in addition to severe gut
inflammation.

Testing:

Observation (clinical diagnosis):

According to the 2010 US Guidelines for food allergy testing (Boyce et al 2010) and the European
Food Allergy Diagnostic Criteria (Burks et al 2012), the gold standard for diagnosis of food allergy is
observation, involving two steps:

Resolution of chronic symptoms after elimination of the offending food from the diet, which may

1. take several days to 2-3 weeks for delayed-type food allergy, and
2. Recurrence of symptoms with reintroduction of the offending food.
   For children with autism, symptoms may include changes in behavior, which may be due to pain
   and discomfort caused by reactions to food allergens.

Safety Note: If the food causes a severe reaction or anaphylaxis shock, then reintroduction of foods should only be done in a physician’s clinic or hospital.

Boyce, J.A., et al (2010). Guidelines for the Diagnosis and Management ofFoodAllergy in the United
States: Summary ofthe NIAJD-Sponsored Expert Panel Report. J Allergy Clin Immunol 126, 1105-
1118.

Burks, A. W., et al (2012). ICON: Food allergy. J Allergy Clin Immunol 129, 906-920.

Diet Log: Keep a diet log, and look for a pattern between symptoms and foods eaten in the last 1-2
days. For delayed-type food allergies, the association between intake of the food allergens and
clinical symptoms are much less evident, so a diet log is helpful to recognize associations in
delayed-type food allergies.

Blood and skin testing: Food allergen specific IgE testing by blood testing (called RAST) or skin
prick testing can be helpful to detect immediate-type food allergies. These tests are readily
available but have a high frequency of false positive results (i.e., many safe foods will be falsely
reported as being allergens), so they should only be used as a guide as to possible foods to
consider removing and then reintroducing. These tests do NOT help diagnose delayed-type food
allergies. Blood IgG testing for food allergens is available but is of questionable reliability.

Patch testing: This involves use of a special patch to hold the food on the skin on the back for 48-
72 hours, to check for delayed reactions – this may correlate with delayed-type cellular immune

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