The aim of this study was to determine the relationship between the constitutional characteristics of the individual and occupational risk factors that affect the occurrence and course of occupational contact dermatitis (OCD) in hairdressing apprentices. The research included 408 hairdressing apprentices from 25 towns in the Republic of Croatia who were examined at the beginning of education and monitored in 3 phases at the end of each school year. The study protocol included questionnaires with questions on self-reported symptoms of hand dermatitis, atopy and working conditions, clinical evaluation of skin changes using the Osnabrueck Hand Eczema Severity Index (OHSI), genotyping of filaggrin (FLG) gene polymorphisms, transepidermal water loss (TEWL) and skin pH measurement and patch testing of students with skin changes lasting 3 months or longer. The OCD incidence rate was 32.3/100 persons per year, while the total three-year prevalence of OCD was 50.3%. Only one student had a mutation of the FLG gene, therefore these mutations were not identified as a risk factor for OCD. At the beginning of education, 45.73% of apprentices reported the existence of atopic diseases, and 7.38% of them atopic dermatitis (AD). In 71.4% of apprentices with a positive reaction to patch testing, contact allergy to occupational allergens was established already during training for the hairdressing profession. Proven risk factors for the development of OCD at the beginning of education were: AD, presence of skin changes and higher hand skin pH. An increase in hand TEWL greater than 5 g/m2/ h could have a predictive value for the occurrence of OCD during schooling. It was noticed that students did not use protective gloves often enough when performing risky hairdressing activities. All of the above indicates the need to improve preventive examinations of apprentices and education on proper skin protection at work.