title: Incidence of immediate and delayed hypersensitivity to Centruroides antivenom.
abstract: OBJECTIVE
  To assess the incidence and course of immediate and delayed hypersensitivity to Centruroides antivenom.
  
  
  METHODS
  We performed a 12-month prospective observation study, with telephone follow-up, evaluating the incidence of anaphylaxis or anaphylactoid reactions and serum sickness after Centruroides antivenom administration. The setting for the study was a poison control center and tertiary care toxicology treatment center. Participants included all patients who received Centruroides antivenom, and no interventions were performed.
  
  
  RESULTS
  For immediate hypersensitivity reactions, 116 patients with grade III or IV envenomation received Centruroides antivenom; 77 of these patients were younger than 13 years. Three patients completed the infusion despite development of rash. A fourth patient with a history of atopy and asthma received epinephrine infusion and an inhaled beta-agonist for transient wheezing that quickly resolved; she was admitted for observation. Nine patients without hypersensitivity reactions were admitted for social reasons, for inappropriate sedation from drugs used before antivenom, or to rule out aspiration; all were discharged within 24 hours. The remaining 106 patients were discharged from the emergency department after resolution of symptoms. Thus 4 of 116 patients had immediate reactions. For patients with delayed reactions, 17 patients were lost to follow-up. Of 99 remaining patients, serum sickness developed in 61% (n=60), as defined by using liberal criteria. Serum sickness responded to oral steroids, antihistamines, or both; mean duration of symptoms with medication was 2.8 days.
  
  
  CONCLUSIONS
  Anaphylactic reactions are uncommon after Centruroides antivenom infusion. Self-limited serum sickness that is easily controlled with corticosteroids and antihistamines commonly follows the use of Centruroides antivenom.
authors.affiliation: Department of Medical Toxicology, Good Samaritan Medical Center, Phoenix, AZ 85006, USA. frankl@samaritan.edu
authors.forename: F
authors.initials: F
authors.lastname: LoVecchio
authors.forename: S
authors.initials: S
authors.lastname: Welch
authors.forename: J
authors.initials: J
authors.lastname: Klemens
authors.forename: S C
authors.initials: SC
authors.lastname: Curry
authors.forename: R
authors.initials: R
authors.lastname: Thomas
mesh_terms: D000328:Adult; D000707:Anaphylaxis / Q000139:chemically induced* / Q000453:epidemiology; D000818:Animals; D000997:Antivenins / Q000009:adverse effects*; D002648:Child; D004342:Drug Hypersensitivity / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000139:chemically induced; D006969:Hypersensitivity, Immediate / Q000139:chemically induced; D015994:Incidence; D008297:Male; D011446:Prospective Studies; D065008:Scorpion Stings / Q000628:therapy*; D012604:Scorpion Venoms; D012605:Scorpions; D012713:Serum Sickness / Q000139:chemically induced
chemical_list: D000997:Antivenins; D012604:Scorpion Venoms