Which of the following is a typical sign of dehydration in children?

Dry mouth and lips are a typical sign of dehydration in children. When a child is dehydrated, their body loses more fluids than it takes in, leading to a decrease in saliva production. This can result in the mouth and lips becoming dry and cracked, which is one of the key visual indicators of fluid loss.

Monitoring hydration status is particularly important in children because they are more susceptible to the effects of dehydration due to their smaller body size and higher metabolic rates. Other typical signs of dehydration might include decreased urine output, decreased skin turgor, and lethargy, but dry mouth and lips are some of the earliest and most noticeable changes.

The other options do not indicate dehydration: increased energy levels would generally suggest that a child is well-hydrated; weight gain is not associated with dehydration, as fluid loss typically leads to weight loss; and frequent urination is usually a sign of adequate hydration or a possible medical condition, rather than indicating a deficit.