Autism and asthma are among the most common chronic diseases in childhood. Both conditions typically present in early childhood and involve altered immune regulation. There has been an increase in asthma and autism prevalence that has not been conclusively explained. They share similar risk factors including prematurity, low birth weight, urban environment and firstborn birth order. A shared inflammatory origin could explain an association between both conditions. Some studies have shown a higher association of asthma in individuals with autism, however other studies have not shown a higher risk of asthma. The association of autism and asthma remains unclear.
Another question is whether autism among patients with asthma leads to more severe asthma outcomes. Two or more chronic conditions can interact and combine to greater disease severity. Children with autism have impaired communication skills. Their reduced ability to recognize and verbalize symptoms can make diagnosis and management more difficult. The association between autism and asthma severity is not known, many children worldwide would be expected to have both conditions. A recent study in the May 2017 issue of Annals of Allergy, Asthma and Immunology examined autism and its effect on asthma. The study looked at whether autism serves as a risk factor for asthma and to compare the severity of asthma on children with and without autism.
Results: Among children with asthma, autism was associated with reduced asthma exacerbations, better results on spirometry breathing tests (better FEV1/FVC ratio and lower odds of airflow obstruction), but autism patients are more often prescribed asthma controller medication. Autism patients had higher asthma prescription rates most likely leading to better control compared to children who were not taking asthma controller medication. The authors of the study speculated that parents of children with autism have a more pragmatic view of risk and benefit and concerns about using inhaled steroids for asthma and are less of a barrier for families affected by autism. This then leads to greater use of controller prescriptions. The authors believe that parents of children with autism may be more motivated to do everything possible to avoid other medical symptoms that might exacerbate autism symptoms.
The authors also stated that their data did not support autism as being a risk factor for developing asthma.
Conclusion: For clinicians it does not seem that having autism is a risk factor for asthma. For children with both autism and asthma, the better asthma outcomes stems from greater medication adherence resulting in better lung function and reduced exacerbations.