title: The clinical spectrum of omega-5-gliadin allergy.
abstract: BACKGROUND
  IgE-mediated allergy to the wheat protein omega-5-gliadin (O5G) is associated with wheat-dependent exercise-induced anaphylaxis (WDEIA), where exercise acts as a cofactor, triggering anaphylaxis after wheat ingestion. The wider application of O5G-specific IgE (sIgE) testing has revealed that the manifestations of O5G allergy extend beyond WDEIA.
  
  
  OBJECTIVE
  This study documents clinical manifestations in a large series of patients with sIgE to O5G.
  
  
  METHODS
  A retrospective clinical audit was performed on adult patients with a positive O5G sIgE (>0.35kU/L) between 2007 and 2013 compared with a group who had negative O5G sIgE. Clinical characteristics and skin prick test (SPT) results were examined.
  
  
  RESULTS
  Sixty-seven patients were characterised, 26 of whom presented with food-dependent exercise-induced allergy, whilst others presented with exercise-induced symptoms without apparent food association (16/67), idiopathic anaphylaxis (10/67), food-induced allergic symptoms without exercise (10/67) or recurrent acute urticaria (5/67). Specific IgE to O5G had 91% sensitivity and 92% specificity for wheat-related allergic symptoms. SPT had sensitivity of 92% and specificity of 84%.
  
  
  CONCLUSIONS
  WDEIA is the most common manifestation of O5G allergy, but patients may present with a variety of allergic manifestations, and wheat allergy is not always obvious on history. Non-exercise cofactors or a lack of cofactors were identified in many patients. A distinctive feature of this allergy is that despite regular wheat ingestion, allergic reactions to wheat occur infrequently. Testing for sIgE to O5G should be considered in patients presenting with exercise-induced urticaria/anaphylaxis, idiopathic anaphylaxis and recurrent acute (but not chronic) urticaria.
authors.affiliation: Division of Human Immunology, SA Pathology, Adelaide, South Australia, Australia.|Clinical Immunology and Allergy, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
authors.forename: T A
authors.initials: TA
authors.lastname: Le
authors.affiliation: Division of Human Immunology, SA Pathology, Adelaide, South Australia, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Al Kindi
authors.affiliation: Clinical Immunology and Allergy, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
authors.forename: J-A
authors.initials: JA
authors.lastname: Tan
authors.affiliation: Allergy and Clinical Immunology, Flinders Medical Centre, Adelaide, South Australia, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Smith
authors.affiliation: Division of Human Immunology, SA Pathology, Adelaide, South Australia, Australia.|Clinical Immunology and Allergy, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
authors.forename: R J
authors.initials: RJ
authors.lastname: Heddle
authors.affiliation: Clinical Immunology and Allergy, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
authors.forename: F E
authors.initials: FE
authors.lastname: Kette
authors.affiliation: Division of Human Immunology, SA Pathology, Adelaide, South Australia, Australia.|Clinical Immunology and Allergy, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Hissaria
authors.affiliation: Clinical Immunology and Allergy, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
authors.forename: W B
authors.initials: WB
authors.lastname: Smith
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000485:Allergens / Q000276:immunology*; D000707:Anaphylaxis / Q000175:diagnosis*; D052179:Antigens, Plant / Q000276:immunology*; D001315:Australia; D015444:Exercise; D005260:Female; D005903:Gliadin / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012882:Skin Tests; D053802:Tryptases / Q000097:blood; D014581:Urticaria / Q000209:etiology; D021182:Wheat Hypersensitivity / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D000485:Allergens; D052179:Antigens, Plant; C475180:omega-5 gliadin, wheat; D007073:Immunoglobulin E; D005903:Gliadin; D053802:Tryptases
keywords: anaphylaxis/diagnosis; exercise; gliadin/immunology; omega-5-gliadin, wheat; wheat hypersensitivity/diagnosis