BACKGROUND: Occupational skin diseases are often responsible for sick leave or job changes, affect mostly young subjects, are costly to society and have been reported as significant predictor of unemployment. OBJECTIVES: To assess, over time, the course of occupational hand dermatitis (OHD) after a specific training, by means of follow-up visits and TEWL measurement, to evaluate skin barrier integrity and if preventive measures for hand skin care provided may influence the course of the disease. METHODS: Workers with a diagnosis of OHD from January 2011 to December 2013 were contacted by telephone, filled in a questionnaire (NOSQ-2002) and were invited to a training course on prevention of skin dermatitis, and to a new clinical evaluation with TEWL measurement. Workers who joined the training programme were asked to undergo a new evaluation after 3 months. A total of 65 subjects without contact dermatitis were recruited as control group. RESULTS: One hundred and one subjects from 143 workers, who were contacted, filled in the questionnaire. Sixty-five of them followed the training course and underwent a new clinical evaluation withTEWL measurements. Ongoing symptoms of subjects decreased from 60.0% to 42.3% 3 months after the training, and the subgroup which strictly adhered to the recommendations given achieved better results (61.9% of symptoms improvement when compared to 29.0% obtained in subjects with partial adhesion to the protocol). TEWL values changed from 21.3 ± 9.6 to 18.6 ± 7.2 g/m²/h (P = 0.001) on the hands and from 16.6 ± 9.0 to 10.5 ± 4.6 g/m²/h (P = 0.001) on the forearm, confirming the skin barrier improvement. CONCLUSIONS: Our secondary prevention intervention was effective, leading to a reduction in clinical signs of dermatitis. TEWL measurement is a useful tool to evaluate skin integrity, mostly in apparently healthy skin, which may have a compromised barrier function, resulting in an exacerbation of the dermatitis.