What Causes Itchy Breasts?

I have had itchy breasts for 20 years and recently started using soap. I switched to dove body wash and the scaling under the breast seems to be going away. I don't know if I had eczema or dry skin from the soap. I have none of the other symptons on the chart. What could have caused that. By the way the scales went away when I used a lubricant on my breast.