What is a common sign of dehydration in infants?

Decreased urine output is a common and significant indicator of dehydration in infants. When an infant is dehydrated, their body conserves water, leading to lower levels of urine production. Normally, infants should produce a consistent output of urine, and any noticeable decrease can signal that they are not receiving adequate hydration. Monitoring urine output is a practical way for caregivers and healthcare providers to assess an infant's hydration status.

In contrast, while increased crying could sometimes indicate discomfort or distress, it is not a specific sign of dehydration. Bright red lips may occur in various conditions but do not specifically correlate with dehydration. Cold extremities can be related to various factors, including poor circulation or exposure to cold, and are not exclusively linked to hydration levels. Thus, decreased urine output stands out as the most direct and reliable sign to identify potential dehydration in infants.