What's new in atopic eczema? An analysis of systematic reviews published in 2007 and 2008. Part 1. Definitions, causes and consequences of eczema.

This review summarizes clinically important findings from nine systematic reviews indexed in bibliographical databases between August 2007 and August 2008, dealing with the definitions, causes and consequences of atopic eczema (AE). One review of diagnostic criteria found that out of 10 sets of criteria, only the UK refinement of the Hanifin and Rajka criteria have been adequately tested (in 19 studies). Another review of 20 named outcome measures found that only three [SCORing Atopic Dermatitis (SCORAD), the Eczema Area and Severity Index (EASI) and the Patient Oriented Eczema Measure (POEM)] had been tested and found to perform adequately. In terms of risk factors for developing disease, a review found that birth by caesarean section increased the risk of asthma and hay fever but not eczema in offspring. A review of cohort studies also found evidence that adverse psychological factors in early life predispose to more atopic disease and a worse prognosis. Another review found that filaggrin gene mutations were a consistently strong risk factor for AE, with a person carrying one of these mutations being over three times more likely to exhibit eczema. It has been suggested that eczema might protect against some forms of cancer, and a detailed systematic review of brain cancers that included 53,233 participants from eight case-control and cohort studies found that having atopic disease was associated with a 39% reduction in glioma risk, a finding that was also present for just those with AE (odds ratio 0.69, 95% CI 0.58-0.82). A further review of case-control and cohort studies failed to find any association between keeping furry pets at birth and subsequent risk of eczema, although pet fur might still exacerbate established disease. In terms of disease consequences, a review found that eczema was the commonest cause of chronic sleep loss in young people, affected the whole family. A review of four economic studies from the US found that the annual cost of AE in the States was as high as $3.8 billion when indirect costs are included.