Validation of epidemiological tools for eczema diagnosis in brazilian children: the isaac's and uk working party's criteria

We performed a cohort study in urban Brazil. Parents/guardians of 1,419 children answered ISAAC phase II questionnaire. Children were examined for skin lesions (UKWP protocol). Two dermatologists examined most cases of eczema (according to ISAAC or UKWP), and a sample without eczema.Agreement between repeat questionnaires on the filter question was poor (kappa = 0.4). Agreement between the 2 dermatologists was fair (kappa = 0.6). False positive reports included scabies in 39% of ISAAC cases and 33% of UKWP cases. Sensitivity and PPV were low (ISAAC: 37.1% and 16.1%; UKWP: 28.6% and 23.8%). Specificity and NPV were high (ISAAC: 90.0% and 96.6%; UKWP: 95.3% and 96.2%). One-year prevalence of eczema was 11.3% (ISAAC), 5.9% (UKWP) and 4.9% (adjusted dermatologist diagnosis). Point prevalence of scabies (alone or not) was 43%, 33% and 18%, in eczemas according to ISAAC, to UKWP and to dermatologists. The reasons why children with eczema were not identified by ISAAC or UKWP were wrongly denying dry skin, itchy rash or personal history of atopic diseases. A limitation is that questionnaire was already validated in Brazil, but not field tested in this specific setting.Studies using UKWP or ISAAC criteria should include a validation arm, to contribute to the understanding of potential limitations of their use in different contexts and to explore solutions. We list specific recommendations.Eczema has recently been proposed by the World Allergy Organization [1] to replace terms such as atopic dermatitis, atopic eczema, atopic eczema/dermatitis syndrome, previously used interchangeably in the literature [2]. Its individual diagnosis is a relatively undisputed matter: a chronic, or chronically relapsing, inflammatory skin disease, characterized by itchy papules, which become excoriated and lichenified, whose distribution pattern changes during lifetime from more generalized eruptions with oozing and crusted lesions in early childhood, to the childhood pattern of typical flexural