## 9 Discussion  
CR is generally divided into AR and NAR. AR represents an important public health issue for both its increasing incidence and its impact on QoL and school and job performance. AR is identified by SPT and/or serum-allergen-specific IgE. The current classification of CR into AR and NAR appears to be obsolete; indeed, it does not consider the rhinitis that produces local IgE in the nasal mucosa known as LAR [61]. A localized immune response in the nose is the disease concept of LAR and the assumption of its definition. The term LAR describes a T2 nasal mucosal inflammatory condition characterized by the local production of specific IgE antibodies and positive NAC in the absence of systemic atopy [61]. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{1}{c}{**Chronic Rhinitis**} & \multicolumn{1}{c}{**SPT 1**} & \multicolumn{1}{c}{**Serum IgE**} & \multicolumn{1}{c}{**Nasal IgE**} & \multicolumn{1}{c}{**NAC 2**} & \multicolumn{1}{c}{**BAT 3**} & \multicolumn{1}{c}{**Reference**} \\ \hline AR & + & +(\(-\)) & +(\(-\)) & + & + & [36; 37] \\ NAR & \(-\) & \(-\) & \(-\) & \(-\) & \(-\) & [36; 37] \\ LAR & \(-\) & \(-\) & \(+(-)\) & + & +(\(-\)) & [36; 37] \\ \hline \hline \end{tabular} 1 SPT: skin pick test, 2 NAC: nasal allergen challenge, 3 BAT: basophil activation test.  
\end{table} 
Table 1: Differential diagnosis of chronic rhinitis. Markers for the diagnosis of rhinitis endotypes. However, the mechanisms underlying LAR are still debated, and some clinical features of LAR are similar to AR, but LAR patients are generally younger than AR ones, with more severe symptomatology and family histories of atopy [60; 61]. Lacking systemic atopy, the differential diagnosis of LAR is assessed by the induction of allergic symptoms such as sneezing, nasal itching, rhinorrhea, nasal obstruction by antigen administration in the nasal mucosa, and the presence of IgE antibodies in the nasal mucosa [48]. Since its first description in the literature, much has been discussed about the \"true\" nature of LAR--i.e., whether LAR is an independent endotype of chronic rhinitis, or whether it is the expression of AR or NAR. More recently, it has been also discussed whether LAR is the evolution or the consequence of another chronic rhinitis endotype, such as AR, NAR, or NARES, thus not representing, per se, an independent endotype [18; 19]. From a clinical point of view, LAR, AR, and NAR are CR characterized by the same clinical symptoms, such as rhinorrhea, sneezing, itching, and nasal obstruction [61]. However, there are some differences between these three subtypes [61]. While rhinosinusitis, sleep disorders, learning difficulties, otitis media with effusion, and reduction in QoL are common in all CR subtypes, allergic comorbidities such as asthma and conjunctivitis are more frequently associated with AR and LAR [61]. A strong association has also been described between asthma, AR, and chronic rhinosinusitis [61]. Furthermore, it has been reported that the association with asthma increases in the pediatric population in the presence of AR [61]. Recent studies have also reported an increase in bronchial symptoms and lower airway symptoms after 10 years of disease evolution in patients with LAR [60]. However, according to the previous literature, LAR seems to not be the first stage of AR, so it should be considered a different entity [11; 54]. Thus, LAR could be an independent entity that does not evolve into AR and involves lower airways [55]. Conversely, ARIA does not consider LAR a distinct disease [32]. While SPT and/or serum IgE are diagnostic tools useful in the assessment of AR, NAC, nasal IgE, and/or BAT are useful for revealing LAR patients (Table 1). Surprisingly, human studies have shown a positive reaction to allergy tests over several years of follow-up in patients with LAR [9; 26; 56; 57].