Both psoriasis and eczema (or atopic dermatitis) cause red, scaly skin rashes and can occur on the same parts of the body which is why sometimes people confuse one for the other. They do have somewhat different symptoms so a dermatologist is the best person to diagnose which skin condition it is and how to treat it. Here are some of the characteristics of psoriasis and eczema and how to tell the difference between the two: