Type IV hypersensitivity from rubber chemicals: a 15-year experience in Taiwan

Allergic contact dermatitis from rubber chemicals is frequent but has not been reported form Asia.

To study the pattern of type IV allergy to rubber chemicals in a Chinese-based population.

A retrospective study was conducted by reviewing the patch test results of 2,235 (604 men, 1,631 women) patients from January 1986 to December 2000.

Ninety-nine patients (4.4%) had one or more positive reactions, 42 (6.9%) men and 57 (3.5%) women. The incidence did not increase throughout the study period. Among thiuram, mercapto, carba and black-rubber mix, thiuram is the most potent sensitizer, mostly for the hand and mercapto mix for the foot. Thiuram allergy is considered occupation related, while mercapto allergy, mostly from rubber slippers, is not typically related to an occupation. A negative correlation between thiuram and carba was found despite the frequent association between these two mixes. A high risk of rubber sensitization was noted in construction, health service, transportation, agriculture and hairdressing workers. A high frequency of concomitant sensitivity to cobalt was found.

This is the first statistically analyzed study of rubber chemical allergy in Asia, which supports major trends concerning rubber chemical allergy from European studies. However, wearing rubber slippers in Taiwan contributes to the high percentage of foot dermatitis. Carba should still be retained in the European standard series because of the coexistence of thiuram and carba in rubber products. The concomitant sensitization to cobalt in rubber-allergic patients needs further evaluations.