I have bad rash on the back of my knees, arms (behind elbows) and around neck. i've been using triamcinolone acetonide cream but rash returns always?

Eczema: The distribution suggests eczema, it is worse in the winter from dry cold conditions. Keep moisturizing your skin regularly, take tepid water short shower, moisturize immediately after and before bed time, see an allergist to check for allergies.

See a dermatologist: It's difficult to say without seeing your rash. Psoriasis is a possibility, as is eczema. But let a professional check it out.