Allergic rhinitis (AR) is a common disease around the world, mediated by type 2 immune responses, and some patients don’t respond well to current standard treatments. This shows AR isn’t a single type of disease but a complex syndrome caused by different internal body mechanisms. Periostin is a key matrix protein sitting downstream of the interleukin-4 (IL-4) and interleukin-13 (IL-13) pathways, connecting type 2 immune responses and nasal mucosal tissue remodeling. This article explains periost