Transdermal Xenobiotics in Newborn Skin

Newborn infants are regularly exposed to a wide variety of topical agents, including treatments for rashes, antimicrobial agents, solvents, and skin barriers or moisturizers. Premature and hospitalized infants are also exposed to topical iodine for antisepsis and to topical analgesic agents. The fact that most of these agents have not been specifically evaluated for use in infants has recently been recognized as a major public health concern. The epidermis of preterm infants is not fully developed, constituting an incomplete barrier to systemic absorption of topical agents. Thus, substances applied to the skin can have adverse systemic effects. Povidone-iodine and steroid creams have been associated with thyroid and hypothalamic-pituitary axis suppression, respectively, in premature infants. Application of topical EMLA (Eutectic Mixture of Local Anesthetics) for analgesia has been implicated in methemoglobinemia in premature infants. Exposure to natural latex in gloves and medical equipment may sensitize infants, leading to the development of airway hyperreactivity and other allergic manifestations. Therefore, it is advisable to limit skin exposure of premature infants to xenobiotics. Further work is required to define safe doses of common agents. In addition, transdermal administration of systemic medications, including methylxanthines, may be practical in premature infants.