Why is my head itchy when I'm sweating?

It's because your skin is perhaps not in a good condition. I think the skin is too dry the kind that produces dandruff. You probobly aren't taking much care of it. A good idea would be to use anti dandruff shampoo & wash your hair at certain times even without using shampoo in order to keep the natural flow.

Ah, I see! I probably do have dandruff. After all, what else could these white specks coming from my hair be?

It might be worth checking for head lice. It would account for white flakes, and the itching. I have small kids and when they get them, I generally gt them, and when I have them it only ever itches when I am hot!

How do I check if I have head lice?

I've had the same problem, although, no dandruff. I think my problem arises from being drenched in sweat all the time. I'm barely ever dry, especially an area like my hairline.

Anyhow, shampoos are definitely the first thing I tried... TAR shampoo did it for me at first, but it stopped working after a year or so. I think that's the active ingredient, TAR.
You might want to try that first.

Now, I'm having to use NIZORAL. Its active ingredient is KETOCONAZOLE. That's really what you got to figure out, ACTIVE INGREDIENTS. The Walgreens brand shampoo had something else that didn't work at all for me. I still itch everyday, but at least it's bareable now. I only have to shampoo once or twice a week. God, it was awful at first... I had to shampoo like every other day when the TAR stopped working.

Sometimes I wonder if these moles on my head might have something to do with it.