Autism Spectrum Disorders and Allergies

Autism Spectrum Disorder (ASD) is a generic term that refers to conditions of development that affect communication, behavior, and social interactions. In general, symptoms begin to appear in young children (before age 3) and persist throughout life. Affected individuals generally have a changed perception of the world and essential social differences that lead to problems of understanding and relationship with others. Since ASD is a spectrum, the severity of symptoms or traits can vary greatly, some with intellectual disabilities, while others work very well and may have higher than normal intelligence (known as Asperger's). .

The exact causes of ASD are still poorly understood, although an atypical development of the brain is at the root of many symptoms. There is evidence that ASD can develop in families and have a genetic basis in some cases. Other causes are thought to be related to maternal health during pregnancy, for example: infection, toxic metal poisoning, exposure to a teratogen / alcohol, and l / # 39; use of SSRIs during pregnancy

What are allergies?

An allergy is an adverse reaction of the body's immune system to certain substances (allergens), which may be certain types of foods (see Food allergies), dust, latex, mold, pollen and animal dander. Immunoglobulins in the body, especially IgE, are at the origin of allergies, although other immunoglobulins may also be involved.

Allergies are common and affect about a quarter of Britons at some point in their lives. Children tend to suffer more from allergies, though they may come out with age. However, other allergies can be contracted later in life, to causes that were not previously a cause of allergy.

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The main symptoms of an allergic reaction (the body's reaction to an allergen) may include the development of a rash, sneeze, runny nose or stuffy nose, breathing wheezing and exacerbation of asthma or eczema. These are usually benign and disappear once the allergen is eliminated. However, in extreme cases, a more severe reaction called anaphylactic shock may occur. It constitutes a medical emergency if it is not treated urgently.

Allergies can usually be managed through the use of over-the-counter medications such as sprays, drops, creams and inhalers. Antihistamines can minimize the severity of symptoms.

It is important to note the differences between an allergy, sensitivity and intolerances. Sensitivity is an exaggerated effect of an ordinary substance such as coffee, which may cause palpitations, for example. An intolerance is the case where large amounts of a substance, such as milk (lactose intolerance), can cause diarrhea or vomiting, without however activating the immune system.

Allergies in people with ASD

Several studies have shown abnormal immune function in people with ASD. This is manifested by an increased frequency of recurrent infections and autoimmunity in children with ASD. This is corroborated by large cohort studies, which have shown increased levels of IgE and IgG in children with ASD. Although allergies are common in children, immune dysfunction seen in some children with ASD may predispose affected children to higher rates of allergies compared to non-ASD children.

A recent study by Guifeng and colleagues (published in JAMA Network in 2018); found a significant positive correlation between allergies and ASD in children. Children with ASD were twice as likely to have a food allergy as children without ASD. This study is purely observational and causality can not be determined, although the strong badociation between ASD and allergy in 200,000 children clearly suggests that both are strongly related.

The question of whether the ASD is at the origin of an allergy (especially a food allergy), or if the allergies are causing the ASD, or if both conditions are related to a third factor is debatable. Some studies have shown that gastrointestinal disorders are more common in children with ASD than in others. It is therefore badumed that the development of a food allergy can be attributed to alterations of the intestinal microbiome and to immune activation, which harms brain development and its functioning via the intestine-brain axis (enteric nervous system).

In summary, the rates of allergies; Food allergies, in particular, are much more common in children and people with ASD than in those who do not. Some badume that a deficiency of the immune system, badociated with alterations of the intestine, could affect brain development as well as the development of allergies. Further research is needed to better describe the badociation between allergies and ASD.

Further reading