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AT-A-GLANCE
Many dermatologic diseases exhibit different manifestations in newborns, infants, and children, and a subset of skin conditions are only encountered in neonates.
Certain neonatal skin conditions require special attention as they may be a sign of a serious health condition.
The medical history and methods of clinical examination in neonates differ from the approaches used with older children and adults. It is very important to elicit a thorough maternal and obstetric history with an emphasis on maternal health and any complications during pregnancy or delivery.
The neonate has increased risk for systemic toxicity from topically applied substances; the risk is even greater in premature infants.
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Neonatal skin diseases are a fascinating and unique spectrum of dermatologic conditions. They encompass a broad range of diagnoses, including manifestations of neonatal or maternal infection, developmental defects, cutaneous features of genetic disorders, birthmarks, malignancy, complications of prematurity, and benign transient clinical findings. An understanding of benign cutaneous conditions of newborns and an ability to identify more worrisome presentations are essential to the care of the neonate.
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Appropriate care of the neonatal patient requires a thorough understanding of the maternal health history, including maternal disease as well as pregnancy complications.
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The neonatal period is defined as the first 30 days of life. Infancy is defined as beginning after the first 30 days of life. Although this chapter focuses on conditions presenting in the neonatal period, some conditions may occur in infancy as well. Even though many neonatal skin diseases are benign and self-limiting, serious disease may occur, and cutaneous manifestations of systemic disease or an associated genetic syndrome should not be overlooked.
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Full-term infants are born between 37 and 42 weeks of gestation. Preterm or premature infants are born before 37 weeks of gestation.
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NEONATAL SKIN PHYSIOLOGY
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The skin with its associated appendages provides several important functions. It serves as a barrier against microbes and environmental and other external toxins, provides thermoregulation, prevents transepidermal water loss, and aids in sensory perception. Knowledge of normal embryologic development and the physiology of neonatal skin is helpful for understanding the adaptive changes that occur after birth and for guiding appropriate skin care in both full-term and preterm neonates.
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The epidermis begins to develop around 6 weeks of gestational age as a basal cell layer and a superficial periderm layer; the periderm does not contribute to the formation of the stratified squamous epithelium and is shed during the end of the second trimester.1 Stratification of the fetal epidermis begins in the eighth week of gestation; terminal differentiation commences first in the skin appendages between the 11th and 15th weeks of gestation and then in the interfollicular epidermis; by 22 to 24 weeks of gestation the epidermis consists of 4 to 5 cell ...