okay well knowing that then I have other suggestions....
If you have scales:
Apply salicylic acid gels to scales to make them easier to remove. Other scale softeners contain active ingredients such as urea, lactic acid, or phenol.
Loosen the scales with a brush or fine-toothed comb.
Shampoo your scalp to remove the scales, using a salicylic acid shampoo or soap. Apply emollients such as petroleum jelly or thick creams, oils, lotions, or ointments while scalp is still damp.
To reduce itchiness:
Use a conditioner after shampooing.
Limit using hot tools for styling.
Use wet towels, cold packs, or cold water on itchy spots.
Try over-the-counter tar shampoos or shampoos with menthol, topical steroids, or oral antihistamines.
For your body:
Dont use scalding hot water or too hot water when showering, bathing and especially when washing your hair. It can irritate it more and cause you more itching.
On your body use really thick creamy lotions right after showering. As in like minutes after getting out. your body absorbs more moisture when its still wet. Also some lotions like eucerin and nuetragena have specific lotions for psoriasis you can get anywhere.
Being overweight actually has something to do with worsening psoriasis conditions so try to be in shape... if you already arent
And maybe see if you can get a sample of the Tea Tree Shampoo to see if that'll help. GL!