Dehydration reduces the body's overall moisture levels, including in the skin. The skin relies on hydration to stay supple and elastic. When the body is dehydrated, skin can become dry, flaky, and irritated. This can affect any part of the body, including the penis, especially the shaft and the head (glans), which are more sensitive to changes in moisture levels. Dehydration and Impotence can lead to urinary tract irritation and more concentrated urine, which could increase the risk of skin irritation around the penis, particularly after urination.