What’s new in atopic eczema? An analysis of systematic reviews published in 2017. Part 2: epidemiology, aetiology and risk factors

This article forms part of a series of annual updates that summarizes the evidence base for atopic eczema (AE). It provides a summary of key findings from 28 systematic reviews that were published or indexed during 2017, and focuses on the epidemiology, aetiology and risk factors of AE. AE is the largest single contributor to morbidity associated with skin disease worldwide, once mortality has been excluded. There is a high prevalence of sleep disturbance in individuals with AE and they take more sick leave than controls. While there is a lack of skin bacterial diversity in patients with AE, there is a relative abundance of Staphylococcus aureus and Staphylococcus epidermidis. Compared with controls, affected individuals more often show an IgE response to S. aureus antigens and have higher serum interleukin-31 levels. Early antibiotic exposure, environmental pollutants, maternal atopy and food allergy are associated with an increased risk of AE, and very preterm birth is associated with decreased risk. Patients with AE have a reduced risk of meningioma, but are more likely to develop attention-deficit hyperactivity disorder compared with controls. Patients with eosinophilic oesophagitis are significantly more likely than unaffected individuals to have AE. There is no significant overall association between AE and allergic contact dermatitis (ACD), and in children referred for patch testing, ACD was more common in those without AE. Hand eczema is more prevalent in patients with AE. There is no association between AE and Type 2 diabetes, hypertension, stroke or myocardial infarction.