Ive Had An Itchy Scalp For The Past Year. It

Ive had an itchy scalp for the past year. It started with sores on the left side of my head. I would scratch off the crust and they would bleed. At one point I had a large infection on the back of my head diagnosed as impetigo. I have been using anti fungal and dandruff shampoo with little relief. Today I noticed some yellow crystals forming again on the left side of my scalp. What is going on?