p-Phenylenediamine sensitization and occupation

p-Phenylenediamine (PPD) is an extreme delayed-type skin sensitizer, and is relevant in both occupational and non-occupational exposures.

To estimate the prevalence of PPD sensitization in a population of consecutive patients with suspected allergic contact dermatitis who attended units of dermatology or occupational medicine in north-eastern Italy and to investigate the association between their PPD sensitization and occupation.

A total of 14,464 patients (67.6% women and 32.4% men) with suspected allergic dermatitis underwent patch testing. The associations between patch test results and occupations were studied by multivariate logistic regression analysis.

In both sexes, PPD sensitization was significantly associated with hairdressing and beauty occupation [women, odds ratio (OR) 6.58, 95% confidence interval (CI) 3.76-11.50; men, OR 22.3, 95% CI 4.18-119]. In the female group, PPD sensitization was also significantly higher in professional drivers (OR 5.31, 95% CI 1.76-16.1), barmaids (OR 1.89, 95% CI 1.04-3.44), and cleaners (OR 1.82, 95% CI 1.24-2.68). In the male group, PPD sensitization was significantly higher in bakers and waiters (OR 13.0, 95% CI 1.38-123), household workers (OR 8.46, 95% CI 1.68-42.8), and printers (OR 5.68, 95% CI 1.50-21.5).

Our study showed that workers in several occupations may be at higher risk of developing sensitization to PPD. It is of importance to reduce possible exposure to PPD-crossreacting substances in these occupations.