Carba Mix: A Useful Indicator of Rubber
Sensitivity
M. Rademaker and A. Forsyth
Summary
The value of carba mix as a contact allergen in the European standard battery of al-
lergens has corne under question. A retrospective analysis of data from 5986 patients
undergoing patch testing revealed that, had carba mix been excluded from the stan-
dard battery, 84 cases of contact dermatitis to rubber compounds would have been
missed (i. e. 1.3% of all patients patch-tested). However, during the same period
there were 83 false-positive reactions to carba mix (i. e. 1.3% of all patients patch-
tested). Carba mix is therefore a useful indicator of rubber sensitivity, although the
high false-positive rate underlines the need for a degree of expertise and experience
in reading patch tests.
Key words:
Contact dermatitis - Carba mix - Rubber sensitivity - European standard
battery
Introduction
The allergens in the European standard battery of contact allergens are under regu-
lar review, and recently discussion has taken place as to the continued inclusion of
carba mix in the battery. Carba mix is a known frequent irritant, and some individu-
als go so far as to consider that carba mix is only useful for discriminating between
contact dermatitis investigators of ability (i. e. those who record carba mix reactions
as irritants) and those without ability (i. e. those who record carba mix reactions as
positives). We have therefore analysed the results of 7 years of patch testing to de-
termine whether carba mix was of value as an indicator of rubber sensitivity.
P. Frosch et al. (eds.), Current Topics in Contact Dermatitis
© Springer-Verlag Berlin Heidelberg 1989