**2. Background**

The first report of local production of IgE in the nasal mucosa was documented in 1975 among patients with typical symptoms of allergic rhinitis and negative allergy evaluation (i.e., negative skin prick tests (SPT) or serum-specific IgE (sIgE)). In this early report, specific IgE antibodies to *Dermatophagoides pteronyssinus* (house dust mite) had been detected in the nasal secretions of patients [1]. Later on, several methods to detect IgE in nasal secretions were evaluated, but only in 1989 a direct measuring technique was established [2]. This was tracked in

2010, by defining the concept *entopy* as opposed to atopy. Although still somewhat controversial, *entopy* addresses local production of IgE in the nasal and respiratory mucosa, while atopy is characterized by serum-specific IgE and positive skin reaction [3, 4]. In recent years advances in documentation of nasal IgE production among patients with typical symptoms of allergic rhinitis substantiated the entity of LAR, which is now accepted and relevant worldwide.
