title: Contact sensitization to 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one (MCI/MI). A European multicentre study.
abstract: The frequency of positive reactions to 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one (MCI/MI) were studied at 22 European contact dermatitis clinics over a period of 1 year. A total of 4713 patients participated. All the patients were patch tested with nickel sulphate, formaldehyde, paraben-mix, and MCI/MI. 19.4% of the patients had positive patch tests to nickel, making this the most common allergen. 3% of the patients reacted to 100 ppm MCI/MI, while 2.6% reacted to formaldehyde and 1.1% to parabens. There was great variation in the frequency of MCI/MI sensitivity among the 22 centres. MCI/MI contact allergy was most common among women and in patients with facial dermatitis, while it was rarely seen in patients with dermatitis on the lower legs. There were no fluctuations in the number of positive patch tests to MCI/MI on a monthly basis when the results from all centres were combined. 117 of the 141 MCI/MI sensitized patients included in the study were retested. 88% had positive patch tests when retested. 101 of the MCI/MI-sensitive patients participated in a double-blind, placebo-controlled product use test. This test showed that 31% of the MCI/MI-sensitive patients had a positive reaction to a MCI/MI-preserved product. Only a few patients reacted to a control product. It is concluded that the preservative MCI/MI is an important new contact allergen.
authors.affiliation: Department of Dermatology, Gentofte Hospital, Hellerup, Denmark.
authors.forename: T
authors.initials: T
authors.lastname: Menné
authors.forename: P J
authors.initials: PJ
authors.lastname: Frosch
authors.forename: N K
authors.initials: NK
authors.lastname: Veien
authors.forename: M
authors.initials: M
authors.lastname: Hannuksela
authors.forename: B
authors.initials: B
authors.lastname: Björkner
authors.forename: J M
authors.initials: JM
authors.lastname: Lachapelle
authors.forename: I R
authors.initials: IR
authors.lastname: White
authors.forename: G
authors.initials: G
authors.lastname: Vejlsgaard
authors.forename: H J
authors.initials: HJ
authors.lastname: Schubert
authors.forename: K E
authors.initials: KE
authors.lastname: Andersen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003877:Dermatitis, Contact / Q000209:etiology*; D004311:Double-Blind Method; D005060:Europe; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009532:Nickel / Q000009:adverse effects; D010328:Patch Tests / Q000379:methods; D011310:Preservatives, Pharmaceutical / Q000009:adverse effects*; D013844:Thiazoles / Q000009:adverse effects*
chemical_list: D011310:Preservatives, Pharmaceutical; D013844:Thiazoles; C011506:2-methyl-4-isothiazolin-3-one; D009532:Nickel; C011421:5-chloro-2-methyl-4-isothiazolin-3-one