title: Atypical nasal challenges in patients with idiopathic rhinitis: more evidence for the existence of allergy in the absence of atopy?
abstract: BACKGROUND
  The pathophysiology of idiopathic rhinitis is unknown although evidence is accumulating to suggest that many patients may have a localized form of allergic rhinitis in the absence of other atopic symptoms and markers. This study compares detailed nasal challenge results obtained from patients with idiopathic rhinitis to those of atopic and normal controls.
  
  
  METHODS
  Patients with idiopathic rhinitis (n = 23), perennial allergic rhinitis (n = 8) and normal controls (n = 8) underwent a normal saline challenge to exclude hyper-reactivity and then bilateral nasal allergen challenges. Nasal patency was assessed by anterior active rhinomanometry.
  
  
  RESULTS
  All of the patients with atopic rhinitis demonstrated positive bilateral allergen challenges. All normal control subjects had bilateral negative challenges. Two patients in the idiopathic group tested positively to saline and were excluded from further study with 62% of the remainder testing positive to allergens. Of the idiopathic patients testing positive, 85% were sensitive to house dust mite.
  
  
  CONCLUSIONS
  A significant proportion of patients with idiopathic rhinitis have positive nasal challenges, the vast majority to house dust mite allergen. These findings add to the weight of evidence that suggests 'localized allergy' may exist in the absence of systemic atopic markers.
authors.affiliation: Department of Otolaryngology - Head and Neck Surgery, Flinder's Medical Centre, Bedford Park, Adelaide, SA, Australia. scarney@ent-surgery.com
authors.forename: A S
authors.initials: AS
authors.lastname: Carney
authors.forename: D G
authors.initials: DG
authors.lastname: Powe
authors.forename: R S
authors.initials: RS
authors.lastname: Huskisson
authors.forename: N S
authors.initials: NS
authors.lastname: Jones
mesh_terms: D000485:Allergens; D000818:Animals; D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; D002415:Cats; D003546:Cysteine Endopeptidases; D004285:Dogs; D006801:Humans; D009297:Nasal Mucosa / Q000276:immunology*; D009299:Nasal Provocation Tests; D011058:Pollen; D012220:Rhinitis / Q000276:immunology*; D025363:Rhinomanometry; D018709:Statistics, Nonparametric
chemical_list: D000485:Allergens; D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; D003546:Cysteine Endopeptidases; C451162:Dermatophagoides pteronyssinus antigen p 1