Try using dead sea salts (Amazon sells) mixed with water and then pour on top of head and forehead/face after washing hair. 1-2 Tablespoons dead sea salt to 1 1/2 cup water. Do not rinse it out. Just dry your hair and leave. This has worked for my husband. You can adjust the salt to water ratio based on results.
We have also had success using shampoo bars made by Chagrin Valley Soap. The neem, tea tree shampoo/bar soap has helped a lot. Conventional shampoos just made things worse. Good luck!
Source: Dr Axe