Significance and Problems of Local Allergic Rhinitis from the Clinical and Pathophysiological Points of View

Allergic rhinitis (AR) is a type I hypersensitivity reaction of the nasal mucosa in response to inhaled aeroallergens, and manifests with clinical symptoms such as watery rhinorrhea, nasal congestion, itching, and sneezing. Serum antigen-specific IgE (sIgE) measurements and a skin test (ST) against aeroallergens have been routinely employed to diagnose AR. Individuals exhibiting symptoms of AR without a positive ST or elevated serum sIgE have been diagnosed as non-AR cases. However, the concept of local AR (LAR) has recently been reported as a clinical entity, mainly and initially in Europe. LAR is characterized by the symptoms of AR without evidence of systemic atopy as assessed by the ST and/or measurement of the serum sIgE. The diagnosis of LAR should be rationally based on the detection of sIgE in the nasal secretions or mucosa, and is now practically diagnosed by a nasal allergen provocation test (NAPT). LAR is a stable phenotype and does not represent the initial stage of conventional AR; however, it is characterized by moderate to severe nasal symptoms, marked impairment of the quality of life (QOL) and rapid progression to symptom worsening. It should also be noted that LAR is often complicated by other atopic diseases, such as atopic asthma and/or conventional AR. While no attention was paid to LAR in Japan for a long time, we reported LAR in Japan this year, for the first time, based on our clinical and experimental studies. According to our study, LAR is supposed to exist with the sensitization by house dust mites or Japanese cedar pollen. This article presents a review about LAR, including the history, concept, diagnostic criteria and therapeutic options, in reference to recent updated publications, including our published study.