Journal of Asthma and Allergy (Aug 2022)
A Pragmatic Primary Practice Approach to Using Specific IgE in Allergy Testing in Asthma Diagnosis, Management, and Referral
Abstract
Pascal Demoly,1,2 Andrew H Liu,3 Pablo Rodriguez del Rio,4 Soren Pedersen,5 Thomas B Casale,6,7 David Price8 1Division of Allergy, Department of Pulmonology, Hôpital Arnaud de Villeneuve, Montpellier, France; 2IDESP Inserm, University, Hospital of Montpellier, Montpellier, France; 3Airway Inflammation, Resilience & the Environment (AIRE) Program, Breathing Institute, Section of Pediatric Pulmonary & Sleep Medicine, Children’s Hospital Colorado, Professor of Pediatrics, University of Colorado School of Medicine, Adjunct Professor of Pediatrics, National Jewish Health, Denver, CO, USA; 4Pediatric Board of the EAACI, University Children’s Hospital, Madrid, Spain; 5GINA Program, Department of Pediatrics, Kolding Hospital, Kolding, Denmark; 6Food Allergy Research and Education (FARE), McLean, VA, USA; 7Department of Medicine and Pediatrics, University of South Florida, Tampa, FL, USA; 8Observational and Pragmatic Research Institute, SingaporeCorrespondence: David Price, Email [email protected]: Asthma afflicts an estimated 339 million people globally and is associated with ill health, disability, and early death. Strong risk factors for developing asthma are genetic predisposition and environmental exposure to inhaled substances that may provoke allergic reactions. Asthma guidelines recommend identifying causal or trigger allergens with specific IgE (sIgE) testing after a diagnosis of asthma has been made. Allergy testing with sIgE targets subpopulations of patients considered at high risk, such as those with frequent exacerbations, emergency visits or hospitalizations, or uncontrolled symptoms. Specific recommendations apply to preschool children, school-age children, patients with persistent or difficult-to-control asthma, patients needing oral corticosteroids or high-dose inhaled steroids, patients seeking understanding and guidance about their disease, and candidates for advanced therapies (biologics, allergen immunotherapy). Allergen skin testing is common in specialized settings but less available in primary care. Blood tests for total and sIgE are accessible and yield quantifiable results for tested allergens, useful for detecting sensitization. Results are interpreted in the context of the patient’s clinical presentation, age, and relevant allergen exposures. Incorporating sIgE testing into asthma management adds objective information to identify specific allergies and can guide personalized treatment plans, which reinforce patient-doctor communication. Test results can also be used to predict exacerbations and response to therapies. Additional diagnostic information can be gleaned from (i) eosinophil count ≥ 300 μL, which significantly increases the odds of having exacerbations, and emerging eosinophil biomarkers (eg, eosinophil-derived neurotoxin), which can be measured in plasma or serum samples, and (ii) fractional exhaled nitric oxide (FeNO), with values ≥ 25 ppb regarded as the cutoff for diagnosis, evaluating inhaled corticosteroid response, and of probable response to anti-IgE, anti-IL4 and anti-IL5 receptor biologics. Referral to asthma/allergy specialists is warranted when the initial diagnosis is uncertain, and when asthma symptoms, impairment, or exacerbations are repeated or severe.Keywords: primary care, allergy, asthma, sensitization, specific IgE, component resolved diagnostics
