Should carba mix be reintroduced into the European baseline series?

Hand eczema and occupational contact allergies in healthcare workers with a focus on rubber additives

“…It has been proposed to reintroduce carba mix into the European baseline series. 24 However, in the present study, as has been reported by others, isolated dithiocarbamate reactions seem to be rare. 21 Thiurams seem to be better markers for contact allergy to both thiurams and dithiocarbamates.…”

“…As a consequence of the present study, only DPG‐free medical gloves are now procured in the Southern Health Care Region. It has been proposed to reintroduce carba mix into the European baseline series . However, in the present study, as has been reported by others, isolated dithiocarbamate reactions seem to be rare .…”

“…Rubber additive contact allergies were the most common occupational contact allergies found. Previous reports have indicated that the frequency of contact allergies to thiuram mix has decreased, 6,24,35 and that the frequency of contact allergy to carba mix (which includes DPG) has increased, 25,35 possibly because of the increase in the frequency of DPG contact allergy. 26 A recent Danish patch test study of HCWs participating in a randomized clinical HE trial 11 found thiuram mix contact allergy in 5%, which is higher than the prevalence of 1.9% found in our study.…”

“…11,15,18,19 Thiurams have been reported to be good markers for contact allergy to dithiocarbamates, 20,21 possibly because of chemical structural similarities. Moreover, in recent years, the frequency of contact allergy to diphenylguanidine (DPG) in surgical gloves has increased, 22,23 and has probably contributed to the increase in the frequency of positive test reactions to carba mix, [24][25][26] as DPG is part of carba mix. However, DPG has been reported to frequently cause false-positive or irritant reactions.…”

Patch test results with rubber series in the European Surveillance System on Contact Allergies (ESSCA), 2013/14

“…Although firm conclusions can probably not be drawn from this observation, this phenomenon may indicate that, in unselected patients, spurious, false-positive reactions are indeed observed, whereas, with a higher a priori likelihood of contact allergy in the RT group, such spurious reactions do not play a similar role. Moreover, the recent increase in the frequency of positive reactions to carba mix observed in earlier ESSCA results (3) and in Odense, Denmark (14) most likely indicates a true increase in sensitization, as an increase only in the frequency of irritant reactions to carba mix is not conceivable. Recently, an increasing frequency of sensitization to 1,3-DPG (part of the carba mix) from medical gloves has been observed (15,16), which also might explain the increasing frequency of carba mix reactions.…”