What Do Dry Hair, Dumps On Lower Head And Rashes Indicate?

I have really dry hair, and bumps on lower back of my head and other rash, all around my head, and my head smells funny. I have had this for over three years and have been to three skin doctors(dermatologists) and all they tell me is that I have ITCHY bumps. And just to do is use dandruff shampoo. But the bumps are getting worse on nape of my neck are spreading up my head and itch like crazy. The lymph nodes on my neck swell near the bumps. What could this be?