PENK and allergic rhinitis: ORM: orosomucoid; APOH: apolipoprotein H; FGA: fibrinogen alpha chain; CTSD: cathepsin D; SERPINB3: serpin family b member 3; GC: glucocorticoids; HIF-1α: hypoxia-inducible factor-1alpha; VEGF: vascular endothelial growth factor; AR: allergic rhinitis; miRNA: microRNA; POSTN: periostin hub gene; CDC25A: cell division cycle 25A; PENK: proenkephalin; TNSS: total nasal symptom score; IL: interleukin; IFN-γ: interferon-gamma; TSLP: thymic stromal lymphopoietin; GZMA: granzyme A; FeNO: fractional exhaled nitric oxide; FnNO: fractional nasal nitric oxide