Background: Rubber additives, mainly vulcanizers and antioxidants, are increasingly a cause of contact dermatitis.

Objective: The aim of the present study was to determine the frequency of type IV allergy to rubber additives.

Methods: Seven thousand patients seen during a 10-year period were evaluated. Of them, 4680 were patch tested with the standard series recommended by the Spanish Group for Research of Contact Dermatitis (GEIDC) and a series of individual rubber additives.

Results: A total of 686 patients (14.7% of those patch tested) had one or more positive reactions to rubber additives. Of these, 582 (84.8%) were men and 104 (15.2%) were women. The incidence of rubber sensitization was especially high among construction workers (47.0%).

Conclusion: Rubber additives are a common cause of occupational contact dermatitis, particularly in construction workers. We postulate that rubber gloves and boots (utilized to avoid contact with sensitizing substances) themselves may be a common cause of contact dermatitis. The high incidence of allergy to some rubber additives, such as thiurams and carbas, indicates that their replacement by other less sensitizing vulcanizers is advisable.