Contact allergy to preservatives – II

To determine whether the prevalence of allergic reactions to certain preservatives warrants their inclusion in a routine series for patch testing, a tray of 14 preservatives was tested in 501 consecutive suspected contact dermatitis patients. More than 1% positive reactions were found with DMDM hydantoin, Kathon CG, and alkyl trimethyl ammonium chloride only. The concentration of alkyl trimethyl ammonium chloride (0.1% aqua) was considered too high. Of 6 patients reacting to the formaldehyde releaser DMDM hydantoin, 4 were positive to formaldehyde. Kathon CG may be an important allergen in the Netherlands, and it is worthwhile for dermatologists there to add it to the standard test series. The recent inclusion of quaternium-15 in the ICDRG standard series appears to be of little value to them.