Autism, Allergies and the Immune System

Autism, Allergies and the Immune System
by Sheri Marino MA, CCC-SLP

In The Function of Allergy: an immunological defense against toxins, (1991), Margie Profet proposes that an “immune response known as ‘allergy’ evolved as a last line of defense against the extensive array of toxic substances that exist in the environment.” Individuals with autism spectrum disorder (ASD) are particularly vulnerable to food and seasonal allergies and the associated symptoms can exacerbate cognitive and behavioral challenges. Individuals with ASD are often medically complex, and being aware of early allergy signs and symptoms, as well available treatment options, can help to provide relief and promote overall wellness.

Recent studies have confirmed a significant rise in food allergies in the US. In 2013 the CDC reported that food allergies among children increased 50% between 1997-2011, similar to the trajectory of the rise in autism. Research suggests that 36% of children with ASD have food allergies. So what is the link?

To be explored in this article:

  • Immune Dysregulation
  • Food Allergy and Sensitivities
  • Eosinophilic Esophagitis (EOE)
  • Seasonal Allergies
  • Oral Allergy Syndrome
  • Eczema
  • Ear Infections
  • Sleep Disorders
  • Mental Health
  • Allergy Testing
  • Treatment
  • Conclusion


Allergies and autism share a common underlying issue within the body’s immune system. Studies show that early life immune disruptions are associated with autism. Individuals with ASD may also have overactive immune systems or an imbalance of pro and anti-inflammatory signals. This immune dysregulation appears to be linked with the development of allergies and asthma. In allergic individuals, pattern recognition of danger signals causes the body to perceive pollen or other triggers as pathogens, and the reactions are similar to that of a virus, minus the fever and myalgia.
Inflammation in the body is an immune system response to toxins, irritants and infections, and contributes to health issues including autoimmune diseases, as well as asthma and allergies. Inflammation from food allergies and food intolerances create reactions in the body which can cause physical and neuropsychiatric symptoms. Immune dysregulation is common in families with autism, especially those with autoimmunity whereby the body attacks its own healthy cells as in Rheumatoid Arthritis, diabetes, and celiac disease. Researchers at the UC Davis Mind Institute have linked maternal inflammation to an increased risk of autism due to maternal antibodies attacking fetal brain tissue. Likewise, a mother’s diagnosis of inflammatory diseases including allergies or asthma increases her child’s risk of developing autism.


Individuals with ASD often have difficult to manage behaviors which can be exacerbated by reactions to food allergens. This is particularly problematic when these symptoms are overlooked by behaviorists and educators who develop behavior plans that fail to address underlying medical issues.

Allergies are an inflammatory response of the immune system which defend the body against what is perceived as danger signals. When a child has a food allergy, immune activating inflammatory proteins send the body into fighting mode by producing antibodies to defend against the invader. This reaction causes allergy symptoms which typically occur within the first few hours after eating an offending food. Food allergens can cause an immediate immune reaction mediated by IgE antibodies, resulting in symptoms from rashes, hives and sneezing, to GI upset and in extreme cases, anaphylactic shock. Anaphylaxis, an acute, potentially life threatening reaction to an antigen, can begin with an itchy rash, swelling in the throat or tongue, shortness of breath, lightheadedness, low blood pressure, vomiting or diarrhea.
At the onset of a reaction, it is common to hear kids complain of itchy mouths and throats or difficulty swallowing. Children with ASD who are non-verbal are particularly challenged in expressing their symptoms; therefore, adults must be aware of the physiological symptoms and behaviors that may indicate an allergic reaction.

Common allergic responses can include:

  • Tingling or itching in the mouth.
  • Hives, itching or eczema.
  • Swelling of the lips, face, tongue and throat or other parts of the body.
  • Wheezing, nasal congestion or trouble breathing.
  • Abdominal pain, diarrhea, nausea or vomiting.
  • Dizziness, lightheadedness or fainting.

Early warning signs in infants can help parents identify the presence of potential food allergens. Dr. Raffi Tachdjian, Allergy/Immunologist at UCLA and Aire Medical in Santa Monica, CA encourages parents to look for signs including bloody stools, vomiting, diarrhea, fussy or erratic behavior, arching of the back and, swelling and hives. Dr. Tachdjian explains “Children with ASD are commonly reactive to cow’s milk (casein) wheat, nuts, eggs, and soy; however, allergy testing should be considered across a broad spectrum of allergenic foods if allergy or sensitivity is suspected.” A consultation with a board certified allergy and immunologist is recommended if food allergies are suspected.

Common Allergenic Foods

  • Peanuts and tree nuts
  • Cow’s milk
  • Eggs
  • Fish and shellfish
  • Soy
  • Wheat

Food Intolerance

Many children experience reactions to foods, however, not all reactions are allergic responses. Intolerance to certain foods or food protein induced enterocolitis (FPIES) can cause symptoms such as diarrhea, constipation, irritability, headaches, decreased attention span, hyperactivity or pain. These symptoms could increase negative behaviors such as aggressions and self-injurious behaviors, therefore, food intolerance should be ruled out when developing behavior plans. A board certified allergy and immunologist can help to identify the presence of IgG antibodies or food proteins that are problematic. If an allergy is noted, removing the offending foods from the diet can generally reverse such GI and behavioral symptoms.

“Leaky Gut”

The microbiome of the human gut is integrated with the immune system and the brain via the gut-brain access. Recent studies show evidence that inflammation in the body begins in the gastrointestinal tract. The gut is the body’s first defense against infection or disease as it is intended to remove toxins and bacteria before circulating nutrients through the rest of the body. Food allergens provoke an immune response, causing inflammation in the lining of the gut. This inflammation, commonly referred to as “leaky gut” or intestinal permeability, allows foreign substances such as undigested food particles, food preservatives and other toxins to enter the bloodstream and cross the blood-brain barrier, possibly exacerbating neuropsychiatric symptoms.

Common Food Intolerances

  • Lactose intolerance
  • Gluten sensitivity
  • Corn and Soy sensitivity
  • Sensitivity to food additives

Picky Eaters and GI issues

Children with ASD frequently have self-selected, restrictive diets. Sensory sensitivities often play a role in food choices; however, food intolerances can also influence food selection. Children with ASD commonly limit their food selection to those foods that contain starchy carbohydrates which are generally tan in color. One theory as to why the “tan food” diet is so common points to a problem in the GI tract. Gastrointestinal reflux disease (GERD) is a common GI disorder which is caused by a weakened lower esophageal sphincter (LES). Food intolerance can cause reflux and heartburn, and starchy carbs may help to settle the burning sensation caused by GERD, influencing food selectivity.


Eosinophilic Esophagitis, also known as asthma of the esophagus, is a condition hallmarked by inflammation and reflux. This swelling of the esophagus can occur from an allergic/immune response and cause abdominal pain, trouble swallowing, vomiting and even a complete obstruction of the esophagus. This allergic condition occurs when a large number of white blood cells, normally not found in this tissue, are present. EOE can only be diagnosed with an endoscopy or biopsy of the tissue. Individuals with a family history of allergies as well as environmental and food allergies are at a higher risk of developing EOE.


Seasonal allergies are reactions to offenders such as pollen, trees, grass etc. as the histamines released in the body cause sneezing, wheezing, itchy/watery eyes, and asthma. Children with nasal allergies are at higher risk for developing asthma caused by inflammation of the airways from exposure to allergens. The CDC reports asthma rates have risen 28% between 2001-2011. Seasonal allergies and asthma can be very difficult to manage for individuals with ASD and frequently increase maladaptive behaviors as a result of both difficult to manage symptoms and/or side-effects of medications.


Oral Allergy Syndrome is a term used to describe itchy or scratchy symptoms in the mouth caused by reactions to raw foods and vegetables in people who have seasonal allergies. Cross-reactivity occurs when proteins in allergens are structurally similar. Cross-reactivity can occur between foods as well as between foods and certain pollens, or even latex. Inflammation in the body from seasonal allergies can also increase sensitivity to food allergens during the high pollen seasons.
Cross-reactive pollen-food:

  • Birch: apple, carrot, peach, plum, cherry, pear, almond, hazelnut
  • Grasses: tomato
  • Ragweed: melons, zucchini, cucumber, kiwi, banana
  • Latex: banana, avocados


Eczema, an atopic dermatitis, is very common in children with ASD and most often has an allergy basis. Children with eczema frequently have food allergies, and food triggers can cause eczema flare-ups. Dr. Tachdjian says “Much like a nickel or make-up allergy, eczema can have an immediate or delayed response and throw a parent off by not correlating in time with a possible food trigger.” Eczema causes itching and discomfort, and a delayed response can make finding the culprit tricky. If eczema patches appear or flare-ups are noted in response to certain food triggers, it is best to consult with a pediatric allergy/immunologist that may help identify the triggers and treat the eczema.


Recurring ear infections are common in children with ASD and lead to an overuse of antibiotics, ultimately affecting the microbiome of the gut. Ear infections are commonly caused by food or, more likely, environmental allergies. As the Eustachian tubes empty, bacteria from stagnating fluid in the nose have an opportunity to enter and multiply causing infection. The uncomfortable pressure in the ear can also lead to increased behavioral responses. Managing allergies may help to decrease the occurrence of ear infections and avoid the overuse of antibiotics.


Nasal congestion and sore throats from seasonal allergic rhinitis often leads to disruptive sleep patterns. Fatigue from interrupted sleep can affect performance in school and also result in an increase in maladaptive behaviors, often times leading to unnecessary behavior protocols. Proper management of allergy symptoms can improve sleep patterns.


The symptoms of seasonal or perennial allergic rhinitis or rhino conjunctivitis and food allergies/sensitivities can provoke irritability, effect sleep, cause fatigue, and many other conditions that impact daily life. Some practitioners in the medical community believe that more complex behavioral and emotional responses are caused by brain and nervous system reactions to foods, additives and preservatives. Sometimes referred to as “brain fog”, or neurotoxicity, symptoms including anxiety, lack of attention, agitation, confusion, weepiness, mania, irritability and jumpiness may be the result of inflammation from antibodies formed against cells in specific areas of the brain, resulting from exposure to allergens. Cow’s milk and gluten are two examples of proteins that interact with opiate receptors in the brain which can cause addiction and withdrawal symptoms. Gluten can be neurotoxic to those with Celiac disease and non-celiac gluten sensitivities have been linked to anxiety, depression, schizophrenia and bipolar disorder. Removing the allergens therefore could decrease inflammation and reduce neuropsychiatric symptoms.


Children with ASD who exhibit symptoms such as rashes, eczema, asthma, GI symptoms, recurring respiratory or ear infections and even behavioral issues, should be evaluated by a board certified allergy and immunologist experienced in treating individuals on the autism spectrum.

There are two methods used to perform allergy testing. Skin prick tests are more sensitive in detecting IgE antibodies which identify food allergens. Food intolerances are detected by the presence of IgG and IgA (secretory) antibodies. Both IgG and IgE antibodies can be detected in blood tests; however there is much debate about the clinical relevance of IgG testing. One school of thought is that IgG antibodies are present in allergic and non-allergic individuals. Detection of IgG antibodies indicates exposure to an antigen but not necessarily an allergy. Alternative theories say the presence of IgG antibodies taxes the immune system by increasing inflammatory responses. Physicians experienced with ASD are more likely to consider IgE, IgG and IgA antibodies.


Allergies are best treated with a combination of behavioral and pharmacological interventions.

Treatment for Food Allergy and Sensitivity

In extreme cases, when an anaphylaxis reaction occurs, administration of an EpiPen (epinephrine) and could be lifesaving. Generally, removing offending foods, or elimination diets, are typically prescribed to avoid food allergies and to decrease food sensitivities. Although there is some controversy, many report the elimination diet helps heal leaky gut and reduce symptoms of ADD/ADHD, autism related behaviors, and other neuropsychiatric symptoms. Showering nightly to remove pollen from the body can help decrease allergy symptoms and improve sleep.


When choosing to use pharmaceuticals, understanding pharmacokinetics and ASD is essential because some medications may have negative side-effects, such as lowering seizure thresholds. Variable metabolic factors including DNA differences and liver enzyme processing can change responses to medications. Likewise, fluctuation in therapeutic to toxic levels of a drug can make safe and effective dosing challenging. Although antihistamines and decongestants can be helpful, individuals need to be monitored carefully for side-effects.

Asthma Treatment

Inhalers are commonly used to treat asthma, although they can be difficult to administer. Nebulizers are frequently used for infants and young children, or anyone who has difficulty with the administration of an inhaler.

Allergy Shots

Allergy shots are the most effective and long lasting treatment for allergies, however, many kids with ASD cannot tolerate weekly shots. For those who cannot tolerate shots, or are unable to swallow pills or take ready tabs, using nasal sprays while they are sleeping can be an effective way to administer medication.

Oral Immunotherapy (OIT)

Oral Immunotherapy (OIT), treating the body with an elimination diet and a slow re- introduction to the antigens found in the trigger foods, may help children with ASD overcome their food allergies. OIT, however, is considered to be experimental and must be supervised by an allergy/immunologist under highly controlled circumstances. As with any experimental treatment, the risk/reward benefit must be weighed.


The medical and mental health complications caused by allergies and immune dysregulation can significantly impact the progress and behaviors of individuals with ASD. Symptoms and medication side-effects are frequently misidentified as maladaptive behaviors, and the underlying medical complexities are often overlooked. An evaluation by an allergy/immunologist experienced in treating individuals with ASD is imperative for effective allergy management to ensure medical stability and to improve educational and therapeutic outcomes.