[Allergic contact dermatitis: the evaluation of positivity in skin tests in the workers of an animal feed plant].

Patch tests were performed on 43 workers employed in an animal fodder plant, a typical dust-laden environment. The aim of the study was to establish and assess the incidence of preclinical sensitization to the substances used, some of which are well known allergens, and identify which of these were mostly responsible. On the whole, the tests did not reveal any major reaction to the allergens used, nor polysensitization. However, an unexpected number of cases was sensitized to phenothiazine, a substance that had not been use for the preceding two years. This observation is of interest since phenothiazine is scarcely allergenic and skin eruptions occur only after photosensitization.