What is a key sign of dehydration in a patient?

A key sign of dehydration in a patient is dark yellow urine. When the body is dehydrated, it has less fluid available to dilute the urine, causing it to become more concentrated and take on a darker color. This occurs because the kidneys retain as much water as possible, leading to a significant increase in the concentration of waste products in the urine, which is reflected in its darker hue.

In contrast, clear urine typically indicates good hydration, as well-hydrated individuals are able to excrete fluid with lower concentrations of waste. Frequent urination often occurs in well-hydrated individuals or in cases of certain medical conditions and is not necessarily indicative of dehydration. A skin rash does not directly indicate dehydration; it can have various causes and should be analyzed based on its characteristics and the overall clinical picture of the patient. Thus, dark yellow urine is a reliable indicator of the need for increased fluid intake.