Fluctuations in the prevalence of chromate allergy in Denmark and exposure to chrome-tanned leather

Background. A recent Danish study showed a significant increase in the prevalence of chromate contact allergy after the mid-1990s, probably as a result of exposure to leather products. Objectives. To reproduce the results by analysing data from the period 1992-2009 at Odense University Hospital, Denmark. The temporal development in the occurrence of chromate contact allergy and assumed causative exposures were investigated. Patients, Materials and Methods. A retrospective analysis of patch test data was performed(n = 8483), and medical charts from patients with chromate allergy (n = 231) were reviewed. Comparisons were made using the chi(2)-test. A test of the reproducibility of the TRUE Test (R) was also performed. Logistic regression analyses were used to test for associations. Results. No significant changes in the prevalence or exposure sources of chromate allergy during 1992-2009 were identified. Leather shoes (24.4%) were the most frequent exposure sources in chromate allergy, and were mainly registered in women, although the difference between men and women was not significant (P = 0.07). Cement and leather glove exposure occurred significantly more often in men than in women (P = 0.002). Foot dermatitis (40.3%) was the most frequent anatomical location, apart from hand eczema (60.6%). The reproducibility of the TRUE Test (R) was 93.3%. Conclusions. Apart from hand eczema, the most frequent clinical picture of chromate allergy was foot dermatitis caused by leather shoe exposure. A tendency for an increasing prevalence of chromate contact allergy from 1997 was shown, but no significant change was detectable.