Local allergic rhinitis: concept, pathophysiology, and management

Local allergic rhinitis (LAR) is a localized nasal allergic response in the absence of systemic atopy characterized by local production of specific IgE (sIgE) antibodies, a T(H)2 pattern of mucosal cell infiltration during natural exposure to aeroallergens, and a positive nasal allergen provocation test response with release of inflammatory mediators (tryptase and eosinophil cationic protein). Although the prevalence remains to be established, a number of patients previously given a diagnosis of nonallergic rhinitis or idiopathic rhinitis are now being classified as having LAR. Culprit allergens responsible include house dust mite, grass and olive pollens, and many others. For the diagnosis of LAR, neither skin prick testing nor determination of the presence of serum sIgE antibodies is useful, and a nasal allergen provocation test is needed to identify the culprit allergen or allergens. In a certain proportion of cases, local sIgE can be detected, and conjunctivitis, asthma, or both can be associated. Whether patients with LAR will have systemic atopy in the future is a matter of debate. Further studies are needed for examine the prevalence of this phenomenon in different areas, to improve the diagnostic methods to better identify these patients, and to develop therapeutic approaches, including the use of immunotherapy.