The reasons for changes in the price rate of any crypto currency can be summarized as changes in the balance of supply and demand in the market -
The reasons for the changes in the balance of supply and demand can be within the market:  when large players influence the price or cross-influences: when investors transfer their funds from altcoin to bitcoin and their balance is violated. Also, external factors, such as attempts to regulate crypto by countries and also negative news about the vulnerability of any crypto currency or the hacking of exchanges, and so on.