8. Prevention
As the underlying skin barrier defects observed in AE are the first step in the atopic march, the prevention of AE is very appealing - and especially in families with known risk factors – highly important. As emollients are the primary management strategy in AE, emollient application at early age is an obvious prevention method for AE. Contradictory data exists on its efficiency. Whereas earlier studies hinted towards a highly effective approach for AE prevention in neonates, this could not be confirmed in recent studies where no evidence was found that daily emollients had a preventive effect in neither a population-based nor a high-risk cohort [145-150]. One factor for the conflicting results could be the formulation of the ointment. Ceramide-based emollients are more efficient in reducing the TEWL, whereas peanut-oil based ointments were reported to be a facilitator for allergy [115, 151]. Due to the barrier defect, emollient components can most likely cross the skin barrier more easily in AE. Even though early supplementation of peanut, cow milk, wheat and eggs was not protective for AE [146], a diverse diet and cheese consumption seem to be beneficial, possibly due to the high microbial diversity found in cheese [152, 153]. In the same direction, pre- and probiotics are potentially protective for AE development [154]. Whereas prebiotics are non-digestional ingredients which promote beneficial bacteria such as Bifidobacterium and Lactobacilli, probiotics are active bacteria which are beneficial for human health [155, 156]. Among them are Bifidobacterium and Lactobacilli , Gram positive, anaerobic bacteria which are potentially capable of producing lactic-acids and antimicrobial substances and bacteriocins, limiting potentially pathogenic gut bacteria [154]. The data on the efficiency of pre- and probiotics is highly controversial, likely due to differences in type or mixture of strains [157]. Orally applied prebiotic Escherichia coli and Enterococcus faecalis in children were ineffective in AE prevention[158]. Contrarily, the administration of probiotics during pregnancy has been confirmed to prevent AE of the children in a meta-analysis of 19 studies [159]. Continuation of probiotics during breastfeeding and then the infant seemed efficient in reducing the risk of AE [157, 160].