I hvew have psoriasis on legs . If not touched, the pimples tend to heal , but same  time causing a big deal of itching , and  once touched again, the sores  show up with more threatening    signs .Am I right , that  if  untouched , these shall vanish in a natural  way ? ( ie., without  need for  steroids ? )
You need to revise your diagnosis. Psoriasis is generally a non-itching condition. Although koebnerization (lesion appears at the place of trauma) is distressing in psoriasis. Pimple like lesion as you told(maybe due to mutate psoriasis) which appears after some infection else where. Psorisis needs steroid, and it should be cautiously tapered whether topical or oral otherwise cause rebound phenomenon. For itching, you can take tab HY Chat Doctor.