I had a similar experience as well. For years and years I had an itchy scalp. Scratching would lead eventually to nasty sores. The itching seems to abate after washing my head but got gradually worse over the following 2 days, until I washed my head again. I was even prescribed some cortisone lotion but to no avail.

One day, at the pharmacy, I saw a medicated shampoo called Nizeral that claimed to kill the fungous that causes dandruff. It dawned on me that the fact my itching got worse over time seemed consistant with something growing (sorry that's a bit gross I know). I bought the shampoo.

Well it was a miracle. The itching stopped immediately. Before I had even finished the bottle, the condition had completely disappeared. It never came back. I am cured.

If this was better known, products line like head 'n shoulders would die out completely.