Which skin condition is characterized by redness and excessive shedding of skin cells?

The characteristic redness and excessive shedding of skin cells are prominent features of psoriasis. This chronic autoimmune condition leads to an accelerated life cycle of skin cells, causing them to build up rapidly on the skin's surface, resulting in thick, scaly patches that are often itchy and sometimes painful. The redness in psoriasis comes from the inflammation and increased blood flow to the areas affected by the skin cell buildup.

In contrast, dermatitis, eczema, and rosacea involve different symptoms and mechanisms. Dermatitis generally involves inflammation without the excessive scaling seen in psoriasis. Eczema can also involve redness and irritation, but it does not primarily present with the same kind of thick, scaly plaques. Rosacea is characterized by redness and flushing, often accompanied by pimples and visible blood vessels, but it does not involve the excessive shedding of skin cells typical of psoriasis. Therefore, psoriasis is the best match for the description provided in the question.