title: Prevalence of sensitization to methylisothiazolinone in an Italian Skin Allergy Unit.
abstract: BACKGROUND
  An alarming increase in the prevalence of sensitization to the preservative methylisothiazolinone (MI), alone or in combination with methylchloroisothiazolinone (MCI), has recently been reported, mainly in Northern Europe. Prevalence data from Southern Europe are scanty.
  
  
  METHODS
  We evaluated the prevalence of contact allergy to MI and MCI/MI among 1392 patients consecutively patch tested in 2012-2013 at the Clinica Dermatologica of San Martino Hospital, Genoa, Italy. The patients were patch tested with 2000 ppm MI aq. in addition to the Italian baseline series. The MOAHLFA Index (Male, Occupation, Atopic Dermatitis, Hand, Legs, Face, Age above 40 years) was registered for all patients. Relevant exposures to MI and/or MI/MCI were determined and the patients' clinical outcome after isothiazolinones avoidance was evaluated.
  
  
  RESULTS
  The prevalence of sensitization to MI showed a steep increase of prevalence from 2.3% in 2012 to 6.9% in 2013 while sensitization to MI/MCI rose from 6.76% in 2012 to 9.04% in 2013. Hand and face dermatitis were significantly prevalent in MI allergic patients. Cosmetics, followed by household products, were the most common sources of relevant exposure to both MI and MI/MCI. Clinical improvement after avoidance of isothiazolinones containing products was reported by 85.3% of followed up patients.
  
  
  CONCLUSIONS
  In Italy the prevalence of MI and MI/MCI contact allergy is alarmingly high and it is increasing.
authors.affiliation: Unit of Dermatology, Department of Health Sciences (DISSAL), University of Genoa, IRCCS AOU San Martino, Genoa, Italy - rs.gallo@unige.it.
authors.forename: Rosella
authors.initials: R
authors.lastname: Gallo
authors.affiliation: Unit of Biostatistics, Department of Health Sciences (DISSAL), University of Genoa, Genoa, Italy.
authors.forename: Alessio
authors.initials: A
authors.lastname: Signori
authors.affiliation: Unit of Dermatology, Department of Health Sciences (DISSAL), University of Genoa, IRCCS AOU San Martino, Genoa, Italy.
authors.forename: Sonia
authors.initials: S
authors.lastname: Gervasio
authors.affiliation: Unit of Dermatology, Department of Health Sciences (DISSAL), University of Genoa, IRCCS AOU San Martino, Genoa, Italy.
authors.forename: Aurora
authors.initials: A
authors.lastname: Parodi
mesh_terms: D000328:Adult; D003358:Cosmetics / Q000009:adverse effects; D017449:Dermatitis, Allergic Contact / Q000453:epidemiology*; D005260:Female; D006795:Household Products / Q000009:adverse effects; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D010328:Patch Tests; D011310:Preservatives, Pharmaceutical / Q000009:adverse effects*; D015995:Prevalence; D013844:Thiazoles / Q000009:adverse effects*
chemical_list: D003358:Cosmetics; D011310:Preservatives, Pharmaceutical; D013844:Thiazoles; C011506:2-methyl-4-isothiazolin-3-one; C011421:5-chloro-2-methyl-4-isothiazolin-3-one