Dry skin and atopic dermatitis are early manifestations of skin barrier dysfunction and inflammation and are the first step in the atopic march leading to food and respiratory allergies through environmental exposure to allergens. The lipid composition of the outermost layer of the skin (the stratum corneum) is crucial in the development of skin barrier dysfunction and has an important interplay with the skin pH, hydrophobic properties and rheological properties. In the first section of this chapter, we review the lipid structure of the stratum corneum and emollient properties that influence barrier function including ceramides, free fatty acids and cholesterol. In the second section, we review petrolatum-based and trilipid emollients in the primary prevention of atopic dermatitis and food allergy; despite promising pilot study data where petrolatum-based emollients were shown to improve stratum corneum hydration, they did not have effects on preventing, delaying or reducing the severity of atopic dermatitis and in one study increased risk of skin infections and showed a trend towards increased food allergy. Primary prevention with trilipid emollients shows promising pilot data but results from larger randomized controlled trials are awaited. The third section outlines other topical therapies, including vitamin D, probiotics, calcineurin inhibitors, and corticosteroids. These have beneficial effect in the management of eczema, and proactive topical steroid application in early infancy has been shown to reduce IgE, and potentially reduce allergic march sequelae, but further research is ongoing in this field.