I want to know the clear difference between eczema, urticaria and psoriasis in terms of cause, symptoms and treatment.

If you can only clarify the cause between them is also ok. im very confused and mixed up since they all are skin diseases and have similar clinical picture. thanks a lot!

Eczema is a local allergy coming as a hyperpigmented patch itchy. Urticaria is some chemical or food substance to which you are allergic to is eaten, causes small itchy swellings over skin all over body. Psoriasis is of unknown cause (some say it is due to mental tension) that forms itchy areas over patches of skin and skin is desquamated as scales of epidermal tissue.