What Causes Rash On Forearms And Legs?

I have quit smoking about 2 weeks ago, immediatley after i developed a rash on my forearms, and upper legs only. I have been to a doctor to rule out bugs or scabies, he gave me a cortizone cream, it is not helping. No- one else in my family has any itching or rash, but it is not going away. Someone mentioned a smoking rash, where nicotine is coming out through the pores? Could this be what is causing my rash?