for Itchy Scalp you may use
Selsun from
Pfizer which contains Selenium Sulfide.
Selsun helps to get rid of dandruff/itchy scalp & many other skin related fungal infections.
Follow the usage instructions & caution carefully & you're good to go.
To prevent hair fall, there's no/any proven effective remedy. IMHO, you should pay attention to your diet & it'll be fruitful in the longer run.