What Causes Itchy And Red Area On Lips?

Yes, I ve been suffering with itchy, red areas on the rim of my lips for a couple of years. The areas move around on my lips. They tingle and itch. Have been to two dermatologists with no results. I ve read about perioral dermatits, but that s not what this is. This affects the edge of my lips and just below or above it. Very frustrated.