Asthma in combination with rhinitis and eczema is associated with higher levels of type-2 inflammation and symptom burden

Background: Asthma, rhinitis and eczema often coexist, especially if there is a history of allergy. Little is known regarding the relation between allergic multimorbidity and the degree of type-2 inflammation. Objective: To investigate subjects with allergic multimorbidity in terms of type-2 markers, immunoglobulin E (IgE) sensitization, respiratory and food allergy symptoms. Methods: A total of 411 children and young adults with physician-diagnosed asthma were tested for exhaled nitric oxide (FENO), total and specific IgE, plasma eosinophil-derived neurotoxin (P-EDN) and blood eosinophils (B-Eos). Respiratory and allergy symptoms were questionnaire-assessed. Allergic multimorbidity was defined based on the presence of rhinitis, or rhinitis and eczema. Results: Asthmatics with rhinitis and eczema (n=141) had higher levels (geometric mean (95% CI)) of type-2 biomarkers: FENO (ppb) (17.8 (15.7-20.2) vs 11.9 (9.4-13.8), p=0.002), B-Eos count (10^9/L (0.21 (0.18-0.24) vs 0.12 (0.10-0.15), p=0.002), total IgE (kU/L) (225 (175-289) vs 55.6 (33.4-92.7), p<0.001), and P-EDN (µg/L) (17.3 (15.9-18.7) vs 14.8 (13.6-16.2), p=0.003), compared with those with asthma alone (n=50). Asthmatics with rhinitis (n=203), and rhinitis and eczema (n=141) were more likely to be sensitized to food and aeroallergens (p<0.05 both) and report symptoms when exposed to those allergens (p<0.001 both). Those with allergic multimorbidity reported more wheezing and asthma attacks during the last year than those with asthma alone (p<0.05 both). Conclusion: Asthmatics with allergic multimorbidity had a higher degree of type-2 inflammation and increased disease burden compared with subjects with asthma alone.