title: Specific IgE to fish extracts does not predict allergy to specific species within an adult fish allergic population.
abstract: BACKGROUND
  Fish is an important cause of food allergy. Studies on fish allergy are scarce and in most cases limited to serological evaluation. Our objective was to study patterns of self-reported allergy and tolerance to different commonly consumed fish species and its correlation to IgE sensitization to the same species.
  
  
  METHODS
  Thirty-eight adult fish allergic patients completed a questionnaire regarding atopy, age of onset and symptoms to 13 commonly consumed fish species in the Netherlands (pangasius, cod, herring, eel, hake, pollock, mackerel, tilapia, salmon, sardine, tuna, plaice and swordfish). Specific IgE to these fish extracts were analyzed by ImmunoCAP.
  
  
  RESULTS
  Median age of onset of fish allergy was 8.5 years. Severe reactions were reported by the majority of patients (n = 20 (53%) respiratory and of these 20 patients, 6 also had cardiovascular symptoms). After diagnosis, 66% of the patients had eliminated all fish from their diet. Allergy to all species ever tried was reported by 59%. In relation to species ever tried, cod (84%) and herring (79%) were the most frequently reported culprit species while hake (57%) and swordfish (55%) were the least frequent. A positive sIgE (value ≥ 0.35 kUA/L) to the culprit species ranged between 50% (swordfish) and 100% (hake). In tolerant patients, a negative sIgE (value < 0.35 kUA/L) ranged from 0% (hake, pollock and swordfish) to 75% (sardine). For cod, the agreement between sIgE test results and reported allergy or tolerance was 82% and 25%, respectively. Sensitization to cod parvalbumin (Gad c 1) was present in 77% of all patients.
  
  
  CONCLUSIONS
  Serological cross-reactivity between fish species is frequent, but in a significant proportion of patients, clinical relevance appears to be limited to only certain species. A well-taken history or food challenge is required for discrimination between allergy to the different fish species.
authors.affiliation: Department of Dermatology/Allergology, University Medical Center Utrecht, PO Box 85500, Utrecht 3508, GA the Netherlands.
authors.forename: Karlijn Jg
authors.initials: KJ
authors.lastname: Schulkes
authors.affiliation: Department of Dermatology/Allergology, University Medical Center Utrecht, PO Box 85500, Utrecht 3508, GA the Netherlands.
authors.forename: Rob Jb
authors.initials: RJ
authors.lastname: Klemans
authors.affiliation: Department of Dermatology/Allergology, University Medical Center Utrecht, PO Box 85500, Utrecht 3508, GA the Netherlands.
authors.forename: Lidy
authors.initials: L
authors.lastname: Knigge
authors.affiliation: Department of Dermatology/Allergology, University Medical Center Utrecht, PO Box 85500, Utrecht 3508, GA the Netherlands.
authors.forename: Marjolein
authors.initials: M
authors.lastname: de Bruin-Weller
authors.affiliation: Department of Dermatology/Allergology, University Medical Center Utrecht, PO Box 85500, Utrecht 3508, GA the Netherlands.
authors.forename: Carla Afm
authors.initials: CA
authors.lastname: Bruijnzeel-Koomen
authors.affiliation: Thermo Fisher Scientific, Uppsala, Sweden.
authors.forename: Asa
authors.initials: A
authors.lastname: Marknell deWitt
authors.affiliation: Thermo Fisher Scientific, Uppsala, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Lidholm
authors.affiliation: Department of Dermatology/Allergology, University Medical Center Utrecht, PO Box 85500, Utrecht 3508, GA the Netherlands.
authors.forename: André C
authors.initials: AC
authors.lastname: Knulst
keywords: Fish allergy; Fish species; Food allergy; Sensitization; Specific IgE