thanks for asking via HCM, Psoriasis is a chronic relapsing and autoimmune disease. You may be having scaly plaques on various parts of the body,scaly lesions on the scalp. Exact cause is not known. Genetic tendency, autoimmunitity,stress,dry wheather...etc may be responsible for precipitation and exacerbation of psoriasis. You consult dermatologist for firm diagnosis and treatment. I usually recommend cap acitretin 10 mg twice a day along with methotraxate 15 mg weekly in three devided doses 12 hourly...for psoriasis.This may be taken for long time till good response. Blood tests may be done to monitor the treatment. For itching, you may take antihistamnics like levocetirizin... Avoid steroid ,as there may be severe flare up after stopping it. you may apply mild steroid cream or calcipotriol oint on the lesions on the psoriatic lesions. She may apply moisturiser to improve the skin texture. you .should avoid soap bath for few weeks.. hope this will clear your facts. regards