title: Aromatic components of food as novel eliciting factors of pseudoallergic reactions in chronic urticaria.
abstract: BACKGROUND
  Pseudoallergic reactions (PARs) against both additives and natural foods have been reported to elicit chronic urticaria, but in natural food the responsible ingredients are largely unknown.
  
  
  OBJECTIVE
  The study was aimed at identifying novel pseudoallergens in food and focused on evaluating tomatoes, white wine, and herbs as frequently reported food items eliciting wheal responses in urticaria.
  
  
  METHODS
  In 33 patients with chronic urticaria and PARs to food (proved by means of elimination diet and subsequent re-exposure with provocation meals), oral provocation tests were performed with field-grown tomatoes, organically grown white wine (whole food, steam distillates, and residues), oily extracts from herbs, and food additives. In addition, skin biopsy specimens from patients were studied for in vitro mast-cell histamine release with tomato distillate alone or on subsequent stimulation with anti-IgE, substance P, and C5a.
  
  
  RESULTS
  Seventy-six percent of patients reacted to whole tomato (steam distillate, 45%; residue, 15%), 50% to food additives, 47% to herbs, and 44% to whole wine (extract, 27%; residue, 0%). Histamine, protein, and high levels of salicylate were only found in residues. The tomato distillate was further analyzed by means of mass spectroscopy, identifying low molecular-weight aldehydes, ketones, and alcohol as major ingredients. In vitro histamine release was not caused by tomato extract itself but was enhanced by means of subsequent stimulation with substance P and C5a but not by anti-IgE.
  
  
  CONCLUSIONS
  Aromatic volatile ingredients in food are novel agents eliciting PARs in chronic urticaria. Histamine, salicylate, and a direct mast-cell histamine release are not involved in this reactivity to naturally occurring pseudoallergens.
authors.affiliation: Department of Dermatology and Allergy, Charité, Humboldt University, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Zuberbier
authors.forename: Christine
authors.initials: C
authors.lastname: Pfrommer
authors.forename: Kirsten
authors.initials: K
authors.lastname: Specht
authors.forename: Stefan
authors.initials: S
authors.lastname: Vieths
authors.forename: Renate
authors.initials: R
authors.lastname: Bastl-Borrmann
authors.forename: Margitta
authors.initials: M
authors.lastname: Worm
authors.forename: Beate M
authors.initials: BM
authors.lastname: Henz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000485:Allergens / Q000009:adverse effects* / Q000737:chemistry*; D002908:Chronic Disease; D005260:Female; D005503:Food Additives / Q000009:adverse effects; D005512:Food Hypersensitivity / Q000209:etiology*; D006636:Histamine Release; D006801:Humans; D018551:Solanum lycopersicum / Q000009:adverse effects / Q000737:chemistry; D008297:Male; D008407:Mast Cells / Q000276:immunology; D008875:Middle Aged; D010946:Plants, Medicinal / Q000009:adverse effects / Q000737:chemistry; D012867:Skin / Q000276:immunology; D014581:Urticaria / Q000209:etiology*; D014920:Wine / Q000009:adverse effects
chemical_list: D000485:Allergens; D005503:Food Additives