Validation of self-reporting of hand eczema among Danish hairdressing apprentices

Background. Hairdressing apprentices have a high incidence of hand eczema. Most studies use self-reported hand eczema as a cost-effective method to estimate the prevalence of hand eczema. No validation studies on self-reported hand eczema among hairdressing apprentices exist. Objectives. To evaluate the validity of self-reporting of hand eczema among Danish hairdressing apprentices. Methods. During their first 2 weeks of training, 502 hairdressing apprentices were enrolled in this study. All apprentices completed a self-administered questionnaire including questions regarding, for example, current hand eczema, and they were all clinically examined for hand eczema three times during the first part of their education by use of the Hand Eczema Severity Index. The validity of self-reporting of hand eczema was measured with the clinical examination as the gold standard. Results. The sensitivity of self-reporting of hand eczema was 70.3%, and the specificity was 99.8%. The positive predictive value was 96.3%, and the negative predictive value was 98.5%. Conclusions. We found good agreement between self-reporting of hand eczema and clinical examination. There was good sensitivity and high specificity. Self-reporting of hand eczema among hairdressing apprentices is considered to be a valid method for estimating the prevalence of hand eczema, although it might underestimate the true prevalence.