Are you washing your hair every day? Stop it. Dry scalp hates frequent washing. You’re literally rinsing away your natural oils before they can do their job.
Try skipping a day or two between washes. Your hair will look a little greasy at first (hello, baseball cap), but your scalp will thank you. When you do wash, use lukewarm water—hot water is the enemy of moisture. Treat your head like a delicate orchid, not a muddy truck.
And please, stop scratching with your nails. I know it feels amazing for two seconds, but it breaks the skin and makes everything worse. Use your fingertips, gently. Yes, it’s less satisfying. No, I don’t care.