摘要
Background: Iodopropynyl butylcarbamate (IPBC) is a new preservative in medic al and cosmetic leave-on products. Al-though cases of allergic contact derma titis to IPBC have been reported, it is not known whether the usual test concent ration of 0- 1% is appropriate for screening tests with IPBC. Objectives: To determine the concentration of IPBC that should be used in screening patch tests . Methods: An analysis was made of data filed by 26 centres of dermatology on pa tch tests performed with one or two concentrations of IPBC (0.1% , 0.2% , 0.3 % or 0.5% ) in 8106 unselected patients. Criteria used to determine the best test concentration of IPBC were the reaction index, the positivity ratio, the ra te of crescendo reactions, and the relations between IPBC reactions and theMOAHL FAindex irritant reactions to sodium lauryl sulphate (SLS), and allergic reactio ns to other contact allergens including preservatives. Results: IPBC 0.1% , 0.2 % , 0.3% and 0.5% yielded 0.5% , 0.8% , 1.3% and 1.7% positive reacti ons, but this increase was accompanied by an even greater increase in doubtful a nd irritant reactions. These figures and the other criteria examined suggested t he range of suitable test concentrations of IPBC to lie between 0.2% and 0.3% . A detailed analysis of MOAHLFA indices and of associations between reactions to IPBC and reactions to other allergens and to SLS showed that most of the posi tive reactions to IPBC 0.2% can be assumed to be allergic ones and that with I PBC 0.2% fewer false-positive reactions can be expected than with IPBC 0.3% . Conclusions: Patch testing with IPBC 0.2% is suggested for patients with ec zema possibly related to preservatives.
Background: Iodopropynyl butylcarbamate (IPBC) is a new preservative in medic al and cosmetic leave-on products. Al-though cases of allergic contact derma titis to IPBC have been reported, it is not known whether the usual test concent ration of 0- 1% is appropriate for screening tests with IPBC. Objectives: To determine the concentration of IPBC that should be used in screening patch tests . Methods: An analysis was made of data filed by 26 centres of dermatology on pa tch tests performed with one or two concentrations of IPBC (0.1% , 0.2% , 0.3 % or 0.5% ) in 8106 unselected patients. Criteria used to determine the best test concentration of IPBC were the reaction index, the positivity ratio, the ra te of crescendo reactions, and the relations between IPBC reactions and theMOAHL FAindex irritant reactions to sodium lauryl sulphate (SLS), and allergic reactio ns to other contact allergens including preservatives. Results: IPBC 0.1% , 0.2 % , 0.3% and 0.5% yielded 0.5% , 0.8% , 1.3% and 1.7% positive reacti ons, but this increase was accompanied by an even greater increase in doubtful a nd irritant reactions. These figures and the other criteria examined suggested t he range of suitable test concentrations of IPBC to lie between 0.2% and 0.3% . A detailed analysis of MOAHLFA indices and of associations between reactions to IPBC and reactions to other allergens and to SLS showed that most of the posi tive reactions to IPBC 0.2% can be assumed to be allergic ones and that with I PBC 0.2% fewer false-positive reactions can be expected than with IPBC 0.3% . Conclusions: Patch testing with IPBC 0.2% is suggested for patients with ec zema possibly related to preservatives.
