Since both psoriasis and eczema can present as dry, red, and scaly rashes, they are often confused with one another. However, they differ significantly.
Psoriasis is caused by an over-activation of the immune system, which results in excessive proliferation of keratinocytes (cells that help regenerate skin) and inflammatory molecules (cytokines). This immune cascade results in distinct areas of thick, red, and scaly patches on the skin.[1]
On the other hand, eczema is caused by immune hypersensitivity (often triggered by allergens) and a dysfunctional skin barrier. Although eczema also presents as dry, red, and scaly skin, people often experience severe itching. This leads to scratching, which results in a vicious cycle that worsens the rash.[2]