This is my lovely significant other, Anoeil. He suffers from sebhorreic dermatitis.
As you can see from the before photo, he was severely distressed about it. We have worked out a routine so that he doesn't have to make that face ever again. And yes, he wears that shirt often. It is cute!
The main source of relief for a red itchy scalp, and surrounding skin, is to try Nizoral. You can find it in places like Walgreens, Safeway, or Target. It's a strong medicated shampoo that also can help with acne. Anoeil uses Nizoral 2-3x a week for a few months until the skin heals and the condition starts to go away. Then he uses a shampoo I picked out for him - Giovanni Triple Tea Tree Treat. This is a great shampoo that is more on the natural side that will maintain scalp balance and health. Use these products as your first line of defense. Give them a few weeks and if you are still suffering, it's probably best to see a dermatologist.