Every time my daughter eats meat her scalp would start itching and by evening her scalp would get flakes. when she don't eat meat she is fine.?

Sounds like allergy: Of course, stop eating meat. This sounds like an allergy either to the meat or a spice/sauce eaten with it. You did not mention the source of meat, such as fish, fowl, or mammal. She could be allergic to beef or chicken but not other meats. Stop all meats until she is clear then introduce only one at a time to determine which should be avoided in the future. And red meats should be tried 1 by 1.

An allergy would be: my first thought ... but having only scalp itching and flaking as a symptom of the allergy would be unusual. You don't say how old your daughter is...beef allergies affect as many as 3 to 5% of children, often associated with cow milk allergy. But most children grow out of these reactions. I think your best bet is to speak with your PCP, then see an Allergy specialist. Best wishes:)