Local Allergic Rhinitis

Abstract

Local allergic rhinitis (LAR) forms a subset of allergic rhinitis (AR), in which systemic antibodies (sIgE) to the triggering allergen cannot be detected or do not exist in the blood or skin, but within the nasal mucosa, they are present and trigger the response. In LAR individuals, the NAPT (nasal allergen provocation test) is positive. It is implicit within allergic rhinitis that the nasal and sinusal mucosa contain sIgE, otherwise a Type I hypersensitivity reaction could not occur, but a specific check for this is seldom undertaken if the symptomatology fits allergic rhinitis and systemic testing (skin and serum) for sIgE is positive. LAR is a frequent component within chronic rhinosinusitis. It is highly probable that patients with LAR or AR show severe symptoms of a chronic nature such as those found in conjunctivitis, asthma or sensitisation to multiple allergens. Where a patient has a clinical picture fitting AR, but cutaneous tests and serum sIgE levels are negative, further investigations are recommended, since otherwise all such cases will be classified as non-allergic rhinitis. Where local sIgE is detectable following naturally occurring exposure to airborne allergens and NAPT is positive, resulting in raised levels of localised tryptase, eosinophil cationic protein (ECP) and sIgE, this helps to make the diagnosis of LAR.