there is!
decentralized exchanges, side chains, atomic swaps are the three solutions for trading cryptocurrencies in a way that you don't need a third party platform to sign up and leave your coins in. with these solutions you will have a decentralized place to meet other traders and do the trade and be done with it.
the downside is that they are not yet improved enough to have all the features of a centralized exchange and they are a bit harder to use for now.