Why Is Psoriasis Returning With Itching And Red Rashes On The Arms, Legs, And Abdomen Despite Using Medication?

Hi dear I have a question!about psoriasis He is treated three times few months later then he start with psoriasis disease effect area are arm legs abdomen again he had itching and red rash Medicine Itraconazol 100mg BD Loratadine 10 mg OD Ketoconazole craem Multi vitamin OD Omeprazole 20 mg OD All medicines are used why psoriasis again starting