Which of the following is a common sign of dehydration in patients?

Dry mucous membranes and decreased skin turgor are indeed common signs of dehydration in patients. When a person becomes dehydrated, the body's fluid levels drop, leading to noticeable changes in specific areas.

Dry mucous membranes typically occur in the mouth and nasal passages, indicating a lack of moisture that is pivotal for various bodily functions, including digestion and respiratory health. Decreased skin turgor refers to the skin's elasticity; when someone is well-hydrated, the skin will quickly return to its original position after being pinched. In dehydrated individuals, skin may take longer to return to its normal state, or it may appear less elastic.

The other options explore symptoms that do not necessarily indicate dehydration specifically. Swollen ankles can be related to various conditions, including fluid retention and heart issues, while high blood pressure is not a direct sign of dehydration but can fluctuate due to various factors, including fluid balance. Excessive sweating could lead to dehydration but is not a direct or definitive sign of it on its own. Thus, the presence of dry mucous membranes and decreased skin turgor are hallmark indicators of dehydration.