Contact dermatitis caused by iodopropynyl butylcarbamate inDenmark

Background Iodopropynyl butylcarbamate (IPBC) is a preservative that may cause contact allergy. The first cases were reported in 1997, and IPBC is currently included in our extended European baseline series in Denmark. Objectives To assess trends during the period 2000-2011 concerning IPBC allergy in Denmark, and to address the question of the significance of concomitant reactions to the thiuram mix. Patients/materials/methods Nine thousand seven hundred and fifty-five (6449 female; 3306 male) patients were patch tested with IPBC and the European baseline series at Gentofte Hospital during 2000-2011. The results were registered in an anonymized database, and analyzed with spss. Results Fifty-four cases of IPBC contact allergy were detected. A significant rising trend during 2000-2011 was observed, with no significant changes during 2006-2011. MOAHLFA index analysis showed that IPBC contact allergy was, in our cohort, significantly more prevalent among male patients, occupational, related to hand eczema, and more frequent among patients over 40 years old. A significant relationship between IPBC and thiuram mix allergy was found. Conclusions IPBC continues to be among the less frequent allergens. A 0.2% concentration in patch testing has contributed to the diagnosis of more sensitizations to this substance. Further studies are needed to clarify the reason for the over-representation of thiuram allergy in patients sensitized to IPBC.