An evaluation of dose/unit area and time as key factors influencing the elicitation capacity of methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) in MCI/MI-allergic patients.
Methylchloroisothiazolinone and methylisothiazolinone (MCI/MI) contact allergy affects 1-3% of patch-tested patients in European centres. The aim of the present study was to evaluate the importance of the factors--time and concentration (dose/per unit area)--in the elicitation capacity by means of a repeated open application test (ROAT) experimental design. The study was designed as a double-blind, placebo-controlled, dose-response ROAT preceded by a diagnostic patch testing. 25 subjects with confirmed MCI/MI allergy and 10 healthy, non-MCI/MI allergic control subjects were exposed to 0.025 microg/cm2 (2 p.p.m.) of MCI/MI/unit area of the skin for 4 weeks. After a wash-out period of at least 4 weeks, the subjects were exposed to 0.094 microg/cm2 (7.5 p.p.m.) of MCI/MI/unit area of the skin for 4 weeks. The study showed the importance of both time and exposure in the elicitation process. It demonstrated that the elicitation threshold for MCI/MI is expected to be in the proximity of 0.025 microg/cm2 although it was not possible to establish a definitive elicitation threshold for MCI/MI in this study.
Zachariae
Claus
C
Department of Dermatology, Gentofte Hospital, University of Copenhagen, 2900 Hellerup, Denmark. clza@gentoftehosp.kbhamt.dk
Lerbaek
Anne
A
McNamee
Pauline M
PM
Gray
John E
JE
Wooder
Mike
M
Menné
Torkil
T
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000009:adverse effects*; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis* / Q000209:etiology* / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D010328:Patch Tests / Q000592:standards; D011310:Preservatives, Pharmaceutical / Q000009:adverse effects*; D013844:Thiazoles / Q000009:adverse effects*; D013997:Time Factors
D000485:Allergens; D011310:Preservatives, Pharmaceutical; D013844:Thiazoles; C011506:2-methyl-4-isothiazolin-3-one; C011421:5-chloro-2-methyl-4-isothiazolin-3-one