Is the irritant benzalkonium chloride a contact allergen? A contribution to the ongoing debate from a clinical perspective

Contact Dermatitis. 2008 Jun;58(6):359-63. doi: 10.1111/j.1600-0536.2008.01327.x.


Background: Benzalkonium chloride (BAC) is a well-recognized irritant. However, doubts exist that it is also a contact allergen.

Objective: Analysis of clinical patch test data addressing the reaction profile and synchronous reproducibility of BAC 0.1% in petrolatum (pet.) and possible increases in risk of BAC contact allergy in certain (occupationally exposed) subgroups. PATIENTS /METHODS: Data of 42 898 patients tested with BAC 0.1% in pet. in 3 different series (topical drugs, ophthalmics, and disinfectants) in the departments of the Information Network of Departments of Dermatology ( between 1996 and 2006 was analysed.

Results: Overall, morphologically 'positive' reactions were rare, 0.6-1.5%, with a total of 41 stronger positive reactions. Concordance, assessed in 3322 patients tested in duplicate, was low (kappa coefficient 0.15, 95% CI: 0-0.31). Positive test reactions were observed significantly more often in the disinfectants series compared with the 2 other series, indicating that suspected exposure to disinfectants may be associated with sensitization. However, variation of stronger BAC test positivity across potentially relevant (occupational) groups was non-significant.

Conclusion: This analysis of routine clinical data and a number of previous reports add further, if weak, evidence to the notion that BAC is a contact allergen, albeit a very rare one.

MeSH terms

  • Adult
  • Aged
  • Allergens / adverse effects*
  • Benzalkonium Compounds / adverse effects*
  • Dermatitis, Allergic Contact / diagnosis
  • Dermatitis, Allergic Contact / epidemiology
  • Dermatitis, Allergic Contact / etiology*
  • Dermatitis, Irritant / diagnosis
  • Dermatitis, Irritant / etiology
  • Disinfectants / adverse effects*
  • False Positive Reactions
  • Female
  • Humans
  • Male
  • Middle Aged
  • Occupational Exposure / adverse effects
  • Patch Tests
  • Preservatives, Pharmaceutical / adverse effects*
  • Prevalence
  • Reproducibility of Results
  • Retrospective Studies


  • Allergens
  • Benzalkonium Compounds
  • Disinfectants
  • Preservatives, Pharmaceutical