Retention of Vernix Caseosa in Newborns for Primary Prevention of Atopic Dermatitis

Atopic dermatitis (AD), also known as eczema, is a common chronic inflammatory skin disease that usually begins in infancy and causes significant itching, discomfort, and sleep disturbance. It affects up to one in five children worldwide and represents a growing public-health problem. Research has shown that genetic and environmental factors contribute to its development, especially those related to skin-barrier integrity and the skin microbiome during early life. Preventing AD before it starts-known as primary prevention-has become an important goal. Vernix caseosa is a naturally occurring, white, creamy substance that covers the skin of newborns at birth. It forms during the last trimester of pregnancy and plays a key role in protecting and hydrating the baby's skin before and after birth. Vernix contains water, lipids, and proteins with antimicrobial and anti-inflammatory properties. Despite these potential benefits, in many hospitals vernix is routinely removed soon after delivery as part of standard newborn cleaning or bathing practices. However, there is little scientific evidence to support early removal, and some studies suggest that keeping vernix on the skin for longer may help the newborn's skin barrier function and reduce colonization by harmful bacteria. The PROTEGO Study (Post-Partum Retention of Vernix Caseosa for Primary Prevention of Atopic Dermatitis, Guarding Skin Integrity and Fostering a Healthy Microbiome) is a randomized controlled clinical trial designed to test whether delaying the removal of vernix caseosa after birth can help prevent atopic dermatitis and improve skin health during the first year of life. A total of 1,383 mother-infant pairs will be enrolled from three maternity hospitals in Santiago, Chile. Participants will be randomly assigned to one of two groups: 1. Retention group: Vernix caseosa will be left on the skin and allowed to dry naturally; the baby's first bath will be delayed according to the study protocol. 2. Remova