title: Prevalence of sensitivity to food and drug additives in patients with chronic idiopathic urticaria.
abstract: BACKGROUND
  Chronic idiopathic urticaria (CIU) is defined as the presence of urticaria most days of the week for a period of 6 weeks or longer. There have been reports of food additive sensitivity in CIU previously, but the prevalence has not been precisely determined.
  
  
  OBJECTIVE
  To determine the prevalence of reactions to food and drug additives in patients with CIU.
  
  
  METHODS
  We challenged 100 patients in our allergy/immunology division with CIU to the 11 additives most commonly associated with reactions: tartrazine (FD&C Yellow 5), potassium metabisulfite, monosodium glutamate, aspartame, sodium benzoate, methyl paraben, butylated hydroxy anisole, butylated hydroxy toluene, FD&C Yellow 6, sodium nitrate, sodium nitrite. All of the patients had a history of CIU for longer than 6 weeks, and 43 reported possible history of food or drug additive sensitivity. Single-blind challenges to all of the additives were performed in the clinic and skin scores were recorded. Subjects with positive challenge tests underwent double-blind placebo controlled challenges.
  
  
  RESULTS
  Of 100 subjects, only 2 had a positive urticarial response on single-blind challenge. Neither of these patients had a positive urticarial response on double-blind placebo-controlled challenge. There were no gastrointestinal, respiratory, or other symptom, and no patients reported late reactions.
  
  
  CONCLUSIONS
  We were able to conclude, with 95% confidence intervals that sensitivity to any of the 11 food and drug additives occurs in fewer than 1% of patients with CIU. Food and drug additives appear to be a rare cause of CIU, and avoidance is not recommended.
authors.affiliation: Division of Allergy, Asthma and Immunology, Scripps Clinic, San Diego, Calif. Electronic address: rajan.jessica@scrippshealth.org.
authors.forename: Jessica P
authors.initials: JP
authors.lastname: Rajan
authors.affiliation: Division of Allergy, Asthma and Immunology, Scripps Clinic, San Diego, Calif.
authors.forename: Ronald A
authors.initials: RA
authors.lastname: Simon
authors.affiliation: Allergy & Asthma Consultants of Rockland and Bergen, West Nyack, NY.
authors.forename: John V
authors.initials: JV
authors.lastname: Bosso
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002908:Chronic Disease; D004311:Double-Blind Method; D004342:Drug Hypersensitivity / Q000453:epidemiology*; D005260:Female; D005503:Food Additives / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011310:Preservatives, Pharmaceutical / Q000009:adverse effects*; D015995:Prevalence; D016037:Single-Blind Method; D014581:Urticaria / Q000276:immunology*
chemical_list: D005503:Food Additives; D011310:Preservatives, Pharmaceutical
keywords: Chronic idiopathic urticaria; Drug additives; Food additives