Iodopropynyl butylcarbamate: a new contact allergen

Iodopropynyl butylcarbamate (IPBC) has been used for years as a fungicide and bactericide for wood and paint preservation without any reports of cutaneous side-effects. During the last few years, it has entered cosmetic products and is temporarily permitted in the EU Cosmetics Directive in a use concentration of 0.1%. In the present study, we report our preliminary experience with patch testing consecutive contact dermatitis patients with IPBC. A patch test concentration of 0.1% seems appropriate for initial screening but deserves further evaluation. Among 311 consecutive patch test patients, 3 patients with a positive patch test to IPBC have been identified. Contact allergy is likely in at least 1 case, based on clinical history, exposure history, patch testing with dilution series, ROAT and chemical analysis.