title: Sensitization to Hymenoptera venoms is common, but systemic sting reactions are rare.
abstract: BACKGROUND
  Sensitization to Hymenoptera venom without systemic sting reactions (SSRs) is commonly observed in the general population. Clinical relevance for a future sting has not yet been investigated.
  
  
  OBJECTIVE
  We aimed to evaluate the effect of these debatable sensitizations with deliberate sting challenges and to monitor serologic changes for up to 2 years.
  
  
  METHODS
  One hundred thirty-one challenges with bees and wasps were performed in 94 subjects with a hitherto irrelevant sensitization. The clinical outcome was recorded, and results of specific IgE (sIgE) determinations, skin tests, and basophil activation tests were correlated to the sting reaction. sIgE levels were monitored in reactors and nonreactors after 3 hours, 1 week, 4 weeks, and 1 year.
  
  
  RESULTS
  Only 5 (5.3%) patients had SSRs, but 41 (43.6%) had large local reactions (LLRs) after the sting. Compared with the general population, there was a 9.5-fold higher risk for LLRs but not for SSRs. Three hours after the sting, sIgE levels slightly decreased, but none of the 94 subjects' results turned negative. After 1 week, sIgE levels already increased, increasing up to 3.5-fold (range, 0.2- to 34.0-fold) baseline levels after 4 weeks. To assess the clinical relevance of this increase, we randomly selected 18 patients for a re-sting. Again, 50% had an LLR, but none had an SSR.
  
  
  CONCLUSIONS
  Although sensitization to Hymenoptera venoms was common, the risk of SSRs in sensitized subjects was low in our study. The sIgE level increase after the sting was not an indicator for conversion into symptomatic sensitization. Currently available tests were not able to distinguish between asymptomatic sensitization, LLRs, and SSRs.
authors.affiliation: Department of Dermatology, Division of Environmental Dermatology and Venerology, Medical University of Graz, Graz, Austria. Electronic address: gunter.sturm@medunigraz.at.
authors.forename: Gunter J
authors.initials: GJ
authors.lastname: Sturm
authors.affiliation: Department of Dermatology, Division of Environmental Dermatology and Venerology, Medical University of Graz, Graz, Austria.
authors.forename: Bettina
authors.initials: B
authors.lastname: Kranzelbinder
authors.affiliation: Department of Dermatology, Division of Environmental Dermatology and Venerology, Medical University of Graz, Graz, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Schuster
authors.affiliation: Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria.
authors.forename: Eva M
authors.initials: EM
authors.lastname: Sturm
authors.affiliation: Department of Dermatology, Division of Environmental Dermatology and Venerology, Medical University of Graz, Graz, Austria.
authors.forename: Danijela
authors.initials: D
authors.lastname: Bokanovic
authors.affiliation: Institute of Zoology, University of Graz, Graz, Austria.
authors.forename: Jutta
authors.initials: J
authors.lastname: Vollmann
authors.affiliation: Institute of Zoology, University of Graz, Graz, Austria.
authors.forename: Karl
authors.initials: K
authors.lastname: Crailsheim
authors.affiliation: Floridsdorf Allergy Center, Vienna, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hemmer
authors.affiliation: Department of Dermatology, Division of Environmental Dermatology and Venerology, Medical University of Graz, Graz, Austria.
authors.forename: Werner
authors.initials: W
authors.lastname: Aberer
mesh_terms: D000328:Adult; D000485:Allergens / Q000276:immunology*; D000818:Animals; D001180:Arthropod Venoms / Q000009:adverse effects*; D005260:Female; D006801:Humans; D006927:Hymenoptera / Q000276:immunology*; D006967:Hypersensitivity / Q000175:diagnosis / Q000276:immunology*; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007299:Insect Bites and Stings / Q000175:diagnosis / Q000276:immunology*; D008297:Male; D063868:Patient Outcome Assessment; D012882:Skin Tests; D013997:Time Factors; D055815:Young Adult
chemical_list: D000485:Allergens; D001180:Arthropod Venoms; D007073:Immunoglobulin E
keywords: Asymptomatic sensitization; IgE determination; basophil activation test; component-resolved diagnosis; intradermal test; large local reaction; sting challenge; systemic sting reaction; total IgE