Assessment of atopic dermatitis using self-report and caregiver report: a multicentre validation study

Background The epidemiology of atopic dermatitis (AD) in the U.S.A. has been described largely via US population-based questionnaire studies. However, the validity of the questions used for self-and caregiver-reported eczema has not been previously demonstrated. Objectives To validate the assessment of self-and caregiver-reported eczema. Methods We performed a prospective multicentre dermatology-practice-based study (three sites) to determine the validity of caregiver-and self-reported ever having eczema and 1-year history of eczema. Questionnaires were administered to unselected patients prior to their encounter. Patients (n = 782) were then evaluated by expert dermatologists trained in utilizing the Hanifin and Rajka criteria for AD. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value were determined. Results Caregiver-reported 1-year history of childhood eczema was found to have a sensitivity (95% confidence interval) of 0.70 (0.59-0.80), specificity of 0.96 (0.93-0.99) and PPV of 0.87 (0.78-0.96) when compared with a physician's diagnosis of AD at that visit. Similarly, self-reported 1-year history of adult eczema was found to have a sensitivity of 0.70 (0.59-0.80), specificity of 0.95 (0.93-0.97) and PPV of 0.76 (0.64-0.85). The specificities and PPVs of a history of ever having caregiver-(0.89, 0.82-0.96 and 0.81, 0.70-0.93) and self-reported eczema (0.97, 0.95-0.99 and 0.91, 0.85-0.97) were high, with a high sensitivity in children (0.83, 0.72-0.95) but not in adults (0.43, 0.37-0.51). Conclusions Self-and caregiver-reported diagnosis of eczema ever or in the past year based on a single question demonstrates sufficient validity for the epidemiological study of AD.