Specific IgE level may predict asthma emergency department visits

Published Online: September 2013

People with asthma have higher immunoglobulin E (IgE) levels than those without asthma. Specific IgE is often used to determine if someone is ‘allergic’ to a particular allergen. The absolute level of the specific IgE has been shown to increase when exposure to the allergen increases, however the ability of specific IgE to predict asthma outcomes is unclear. In a study published in The Journal of Allergy and Clinical Immunology: In Practice titled “The Relationship Between a Specific IgE Level and Asthma Outcomes: Results for the 2005-2006 National Health and Nutrition Examination Survey” Arroyave et al demonstrated that the level of specific IgE to certain indoor allergens may be predictive of emergency department (ED) visits due to asthma in both adults and children.  
In this study, specific IgE levels among 351 children and 390 adults with asthma who participated in the 2005-2006 NHANES survey were analyzed to examine the relationship between specific IgE to indoor allergens and asthma outcomes. Both wheeze and asthma ED visits were studied. The authors took age, gender, race, education and poverty status into account in their analysis and found that in children, as specific IgE to cockroaches, rats, and Aspergillus mold increased, so did the probability of an asthma ED visit. Asthmatic children with a moderate level of allergy (between 0.70 kU/L and 3.5 kU/L) to cockroaches were 1.5 times more likely to have an asthma ED visit than children with no allergy to cockroaches, while children with extremely high levels of allergy (greater than 17kU/L) were 7 times more likely to have an asthma ED visit. Children with extremely high levels of rat allergies were 17 times more likely to have an asthma ED visit.  In asthmatic adults allergic to dust mites, their likelihood of having an asthma ED visit increased as the allergy level increased.
These findings suggest that the absolute level of allergy to certain indoor allergens could be used by clinicians to predict asthma ED visits; the higher the allergen level to rats, cockroaches, mold and dust, the higher the probability of an ED visit. Moreover, since the level of IgE in the blood goes up when a person is exposed to that allergen, clinicians could use the absolute IgE level to determine which allergens a patient may be exposed to in the home and to recommend exposure remediation. Specific IgE levels could be a useful tool in the clinician’s toolbox in the treatment of both childhood and adult asthma.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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