A 6-month-old child has developed skin irritation due to an allergic reaction. He has been prescribed a topical skin ointment. The nurse will consider which of the following before administering the drug.

Choice A rationale The infant's skin has a larger surface area to body weight ratio and a thinner stratum corneum (outermost layer) compared to an adult's. This increased permeability and surface area enhance the systemic absorption of topically applied medications, raising the risk of toxicity, a crucial consideration for safe drug administration in infants. Choice B rationale Infants actually have a greater body surface area relative to their weight compared to adults, which contributes to the enhanced systemic absorption of topical drugs. Therefore, the nurse must be more concerned, not less, about the body surface area and its role in drug absorption and potential toxicity. Choice C rationale The maturity and structure of the blood vessels are not the primary factors affecting the absorption rate of topical medications across the skin barrier. The most significant physiological factor influencing topical drug absorption in infants is the increased permeability of the epidermis and the large surface area to body weight ratio. Choice D rationale Infants have increased, not decreased, absorption rates of topical drugs due to the physiological immaturity of their skin barrier. This means the drug penetrates the skin and enters the bloodstream more readily, which necessitates cautious use and careful monitoring to prevent systemic adverse effects.