Is the question 'Have you had childhood eczema?' useful for assessing childhood atopic eczema in adult population surveys?

Atopic eczema (AE) is a major risk factor for hand eczema. In Scandinavian population-based studies, the occurrence of AE in childhood has often been assessed by the question 'Have you had childhood eczema?' In the present study, this question was validated. A questionnaire was sent to 600 cases with AE and 600 controls without eczema or allergic disease, identified in school medical records from the 1960s. The response rate was 70.5%, and the mean age of the respondents was 36.7 years. The specificity of the question was 70.7% and the sensitivity 89.9%. The sensitivity was higher and the specificity lower in a subgroup with current hand eczema compared with a group without hand eczema. The results showed that the question overestimated the prevalence of AE in childhood by a factor of 1.6. When used for risk assessment, the question provided a better estimate of the risk of current hand eczema as compared with the lifetime risk of hand eczema. In conclusion, the validated question overestimated prevalence of childhood AE and may overestimate AE as a risk factor for hand eczema in adult population surveys.