Psoriasis or pityriasis rosea. Frequent)

My younger brother had experience dandruff like something on scalp 2 weeks ago then brown patches surrounding pinkish,reddish color radiated on whole body above legs ,back,neck , abdomen everywhere . No previous history , no case of psoriasis in family before this . Itching occurs while touching them , we r so troubled whether it's psoriasis or pityriasis rosea .one homepathic govt physician diagnose psoriasis while one Ayurved skin specialist told it's pityriasis rosea, we r unable to diagnose what it is. Patient details- Harshvardhan Age - 13 yrs Occurence of the disease- 2-3 weeks Itching, redness, pinkish color with th brown patches. Occurence of viral infection ,pus in fingers in previous two years which is minor. No family history of psoriasis. Eating habit - veg + nonveg ( very less frequent)