Itchy Scalp - Why it happens?
You have dry skin, lice or a buildup of yeast called Pityrosporum, which is always on your skin and loves to feed on dead scalp cells, a.k.a. dandruff.
The Solution of Itchy Scalp
Start using a dandruff shampoo containing yeast killing ketoconazole, such as Nizaral antidandruff shampoo.
Avoid hair salves for a few days to see if the gel is what's causing the problem. If it is, use the goop less often, dilute it with water, or look for an allergen-free brand. Some shampoo additives like sodium sulfate and sodium lauryl sulfate, which can strip your scalp of natural oils. If you have lice, use OTC remedies available at the chemists to get rid them. Several applications may be needed before you achieve a complete wipe out, as the eggs (nits) are more difficult to dislodge.
How to Prevent Itchy Scalp
The directions for some dandruff shampoos suggest leaving the suds on your scalp for 5 minutes. It's better to lather up once to remove any buildup of dead skin, then rinse and repeat so the shampoo can kill the excess yeast.
For lice, periodically check your kids' scalps before they're overrun by the critters.