What are signs of vasoconstriction in an infant or child?

Weak distal pulses are indeed a sign of vasoconstriction in an infant or child. When the body experiences vasoconstriction, blood vessels narrow, which can lead to a decrease in blood flow, especially to the extremities. As a result, the pulse in the peripheral areas, such as the hands and feet, may become weak or difficult to detect. This situation indicates that the body is prioritizing blood flow to vital organs, which is crucial in maintaining adequate perfusion under stress or during illness.

The other options present signs that do not specifically indicate vasoconstriction. A rapid heart rate may occur as a compensatory mechanism for various reasons such as fever, dehydration, or shock. Fever is typically associated with infection or inflammation rather than vasoconstriction. Cold extremities can indicate poor perfusion or hypothermia but may not exclusively point to vasoconstriction, as they can also be a sign of other conditions. Weak distal pulses are the most direct indicator of this physiological response in children.