title: Octylisothiazolinone, an additional cause of allergic contact dermatitis caused by leather: case series and potential implications for the study of cross-reactivity with methylisothiazolinone.
abstract: BACKGROUND
  Octylisothiazolinone (OIT) is used as an antifungal agent by the leather industry.
  
  
  OBJECTIVE
  To show sensitization to OIT from leather, and to highlight the potential implications when cross-reactivity between OIT and methylisothiazolinone (MI) is studied.
  
  
  METHODS
  Two patients with allergic contact dermatitis caused by a leather belt and shoes, respectively, were patch tested with methylchloroisothiazolinone (MCI)/MI, MI, MCI, OIT, and benzisothiazolinone (BIT). High-performance liquid chromatography with ultraviolet detection (HPLC-UV) was used to detect isothiazolinone derivatives in leather goods. Additionally, files of OIT-sensitized patients, observed at the KU Leuven department during the period 1990-2015, were retrospectively analysed.
  
  
  RESULTS
  Both patients had been primarily sensitized to OIT, but the diagnosis in one of them could be achieved only when a higher patch test concentration of OIT (1000 ppm pet.) was used. HPLC-UV confirmed the presence of OIT in their leather goods. Non-relevant sensitization to MI was noted in both cases. Four additional cases of OIT sensitization from leather could be retrieved from the KU Leuven database.
  
  
  CONCLUSIONS
  Non-occupational sensitization to OIT from leather may occur. Patch test concentrations of >250 ppm pet. may be necessary for diagnosis, and to show cross-reactivity with MI. Safer use limits for OIT in the leather industry may be needed.
authors.affiliation: Department of Dermatology, University Hospital Antwerp and University of Antwerp, 2650, Antwerp, Belgium. olivier.aerts@uza.be.
authors.forename: Olivier
authors.initials: O
authors.lastname: Aerts
authors.affiliation: Department of Pharmaceutical Sciences, Research Group Natural Products and Food - Research and Analysis (NatuRA), University of Antwerp, 2610, Antwerp, Belgium.
authors.forename: Hans
authors.initials: H
authors.lastname: Meert
authors.affiliation: Department of Pharmaceutical Sciences, Research Group Natural Products and Food - Research and Analysis (NatuRA), University of Antwerp, 2610, Antwerp, Belgium.
authors.forename: Elien
authors.initials: E
authors.lastname: Romaen
authors.affiliation: Department of Dermatology, University Hospital Antwerp and University of Antwerp, 2650, Antwerp, Belgium.
authors.forename: Julie
authors.initials: J
authors.lastname: Leysen
authors.affiliation: Department of Dermatology, University Hospital Antwerp and University of Antwerp, 2650, Antwerp, Belgium.
authors.forename: Lucretia
authors.initials: L
authors.lastname: Matthieu
authors.affiliation: Department of Pharmaceutical Sciences, Research Group Natural Products and Food - Research and Analysis (NatuRA), University of Antwerp, 2610, Antwerp, Belgium.
authors.forename: Sandra
authors.initials: S
authors.lastname: Apers
authors.affiliation: Department of Dermatology, University Hospital Antwerp and University of Antwerp, 2650, Antwerp, Belgium.
authors.forename: Julien
authors.initials: J
authors.lastname: Lambert
authors.affiliation: Department of Dermatology, University Hospitals KU Leuven, 3000, Leuven, Belgium.
authors.forename: An
authors.initials: A
authors.lastname: Goossens
mesh_terms: D000005:Abdomen; D000328:Adult; D002851:Chromatography, High Pressure Liquid; D003020:Clothing / Q000009:adverse effects; D003429:Cross Reactions; D017449:Dermatitis, Allergic Contact / Q000209:etiology*; D005260:Female; D005533:Foot Dermatoses / Q000209:etiology*; D005659:Fungicides, Industrial / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010328:Patch Tests; D011310:Preservatives, Pharmaceutical / Q000009:adverse effects; D012775:Shoes / Q000009:adverse effects*; D013844:Thiazoles / Q000009:adverse effects*
chemical_list: D005659:Fungicides, Industrial; D011310:Preservatives, Pharmaceutical; D013844:Thiazoles; C011506:2-methyl-4-isothiazolin-3-one
keywords: CAS no. 26530-20-1; allergic contact dermatitis; biocide; cross-reaction; fungicide; high-performance liquid chromatography; leather; methylisothiazolinone; octylisothiazolinone; shoes