Anytime something rises this suddenly and sharply, you should definitely be skeptical.
I don't fully understand the alt-coin pump going on, nor does anyone. I can only threorize that it involves run-off from the sudden spike in Japanese crypto-currency interest.
You'd be right to be skeptical. Think of it as the Internet in 1994, no one knows, which cryptocurrency will reign supreme. Some of the coins are pump and dump but now more altcoins have fully working teams who are identifiable. An example of this is Vitalik Buterin of Ethereum, Amanda Johnson of Dash or Reggie Middleton of Veritaseum.
As professionalism comes into this space, the rubbish coins will disappear and the cream will rise to the top.