What are the signs of dehydration in children?

The signs of dehydration in children are critical to recognize, as dehydration can lead to serious health complications. The choice that includes dry mouth, decreased urine output, and lethargy accurately captures key clinical indicators of dehydration.

A dry mouth suggests that the child is not adequately hydrated, which is one of the first noticeable signs of fluid loss. Decreased urine output is a crucial parameter in assessing hydration status, as a significant reduction in urine volume can indicate that the body is conserving fluids due to dehydration. Lethargy reflects a reduction in energy levels and can be a result of decreased blood volume and electrolyte imbalances that affect overall cellular function.

Other options present elements that may relate to dehydration but do not encompass the most direct signs associated with the condition. For instance, while nausea, vomiting, and diarrhea can contribute to a child's dehydration status, they are not the signs indicating dehydration's direct impact on fluid balance. Meanwhile, fever, dizziness, and headache may arise from various medical conditions, not exclusively dehydration, and do not provide the same level of direct indication of fluid loss that the features mentioned in the correct answer do. Thus, the selection effectively identifies classic signs that should prompt further evaluation of hydration status in children.