Concomitant contact-allergic reactions to iodopropynyl butylcarbamate and iodine.

We suspect that, notwithstanding the absence of firm evidence for IPBC being dehalogenated to produce free iodine in animals or in humans, the patch test reactions to IPBC in iodine-allergic subjects were possibly caused by free iodine released from this preservative agent, thus underlining the EU restrictions regarding the use of this preservative in cosmetics.