Occupational dermatitis in animal feed mill workers.

In an epidemiological study of occupational dermatitis in 15 different northern Italian animal feed mills, 204 workers were interviewed, examined and patch tested to 34 allergens, selected from the additives most commonly used in the animal feed mills under consideration. The prevalence of occupational contact dermatitis was 13.7% (28/204): 7.8% (16/204) irritant contact dermatitis and 5.8% (12/204) allergic contact dermatitis from animal feed additives. Among the latter, there were sensitizations, to our knowledge hitherto unreported in the literature: to indigo carmine (2 cases), monensin sodium (1 case), thiabendazole (1 case), methylchlorpindol (1 case) and amprolium hydrochloride (1 case). 3.9% (8/204) of the workers complained only of pruritus sine materia on exposed areas of the body. Contact dermatitis increased with respect to duration of employment: the difference in the rate of contact dermatitis between workers employed in animal feed mill for greater than 10 years and those employed for less than 10 years was statistically significant (p less than 0.05). 6.8% (14/204) had latent sensitivity, which was more frequent in workers with less than 1 year of employment with respect to more experienced colleagues.