A cohort of occupational dermatology patients will be set up at the University Hospital Heidelberg, Germany. In a 3-year prospective cohort study, the so-called molecular classifier will be applied in 262 patients to better differentiate between eczema and psoriasis. A retrospective cohort of 282 occupational health patients with the same suspected diagnosis but no molecular classifier designation was used as a control group. In 5 follow-up visits during 3 years, data will be obtained on diagnoses, disease course and severity, absence from work, occupation and quality of life. The research questions address whether early diagnoses will help to better identify the efficient treatment, disease course, absence from work and continuance of occupation. The study is sponsored by the public statutory employers' liability insurance (Deutsche Gesetzliche Unfallversicherung [DGUV]).