What's the difference in appearance between atopic dermatitis and contact dermatitis?

General v. localized: Atopic dermatitis is a chronic condition that is generalized over the entire skin surface, but usually most obvious in the "flexor" areas (crooks of elbows & knees, neck, underarms). Contact dermatitis is localized to the area of contact, and is often streaky in appearance due to the effect of the contact brushing against the skin surface. Atopy also tends to be symmetrical; contact is not.