Psoriasis often present so similarly to Atopic Dermatitis that most patients cannot tell the difference, and just think of it as eczema.
Although both Atopic Dermatitis (commonly categorically referred to as Eczema) and Psoriasis can manifest anywhere in the body, here are some useful ways to differentiate:
Location:
You are more like to find Psoriasis lesions on your hairline or your scalp, or in your butt crack. Additionally, Psoriasis tends to present at the kneecap or on the pointy parts of your elbows, while the classical presentation (especially in children) would be in the inner elbow or behind the knees. Both of them are as likely to have lesions appearing around the ears.
Auspitz:
Atopic Dermatitis is an atopic condition, and may be accompanied other atopic conditions Allergic Rhinitis and/or Asthma. It has a more complex etiology (including genetic causes, a compromised skin barrier and environmental/food triggers. Eczema lesions present with great variety.
Psoriasis is an autoimmune condition characterized by excessive production of skin cells. What appears are these silvery/whitish scales that leave a small blood stain when peeled off. This is called the Auspitz sign.
Itch levels:
Atopic Dermatitis is generally much more itchy than than Psoriasis, although there is a component of itch in both conditions.
