title: Sensitization prevalence for benzalkonium chloride and benzethonium chloride.
abstract: BACKGROUND
  Benzalkonium chloride (BAK) and benzethonium chloride (BEC) are well-characterized skin irritants and rare sensitizers, but optimal testing for allergic contact dermatitis (ACD) is not established.
  
  
  OBJECTIVE
  Sensitization prevalence was sought, and several patch testing concentrations and vehicles were compared.
  
  
  METHODS
  One hundred forty-two patients tested to the standard screening series for evaluation of dermatitis consented to additional tests including BAK 0.15% aqueous (aq), BAK 0.15% petrolatum (pet), BEC 0.15% aq, and BEC 0.5% aq. Follow-up to assess clinical relevancy included early and late patch test reads, 1-month clinical follow-up, and long-term phone calls. Patients were categorized as definite, possible, or unlikely to have ACD to BAK and/or BEC.
  
  
  RESULTS
  Atopy was not associated with patch test reactions (P = 0.154). Seventy-five percent (6/8) of the patients with possible ACD to BAK had coreactions with BEC. Testing to both BAK 0.15% pet and 0.15% aq would have identified 91% of those with possible ACD to BAK, twice as many than if only BAK 0.1% aq from the standard series was used.
  
  
  CONCLUSIONS
  Sensitization to BAK and BEC, although rare, does occur. Weak and morphologically irritant reactions at day 7 reading can be relevant. We recommend testing to BAK 0.15% aq and 0.15% pet to increase sensitivity and having patients undergo long-term follow-up.
authors: Department of Dermatology, University Hospitals Case Medical Center, Cleveland, OH, USA.
authors: Harry
authors: H
authors: Dao
authors: Chris
authors: C
authors: Fricker
authors: Susan T
authors: ST
authors: Nedorost
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000485:Allergens / Q000276:immunology*; D001548:Benzalkonium Compounds / Q000009:adverse effects*; D001558:Benzethonium / Q000009:adverse effects*; D002648:Child; D017449:Dermatitis, Allergic Contact / Q000209:etiology* / Q000276:immunology; D005260:Female; D006801:Humans; D007509:Irritants / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010328:Patch Tests / Q000379:methods; D011310:Preservatives, Pharmaceutical / Q000009:adverse effects*; D015995:Prevalence; D055815:Young Adult
chemical_list: D000485:Allergens; D001548:Benzalkonium Compounds; D007509:Irritants; D011310:Preservatives, Pharmaceutical; D001558:Benzethonium