What medical condition does "dry skin" refer to specifically?

The term "dry skin" specifically refers to xeroderma, which is a condition characterized by insufficient moisture in the skin. This can lead to skin that feels rough, itchy, or even painful. Xeroderma is generally a benign issue that can arise from various factors such as environmental conditions, aging, or underlying health issues.

In contrast, psoriasis and eczema are both inflammatory skin conditions that may involve dry skin as a symptom, but they are not synonymous with it. Psoriasis is often characterized by red, scaly patches and is linked to an immune system dysfunction. Eczema refers to a group of conditions that cause the skin to become inflamed or irritated, often with itchiness and rashes, which can also lead to dryness but is primarily an inflammatory response rather than simply a dryness issue.

Dermatitis, a broader term, encompasses various skin inflammation conditions, which can also result in dry skin but is not specifically defined by it. Therefore, xeroderma accurately captures the essence of "dry skin" as a distinct medical condition.