Following list is increasing automatically

I've noticed my 'Following' (not 'Followers') list is increasing all by itself. I have to unfollow all the time and have tried blocking some of them only to find soon after they're back on my 'following' list. It's driving me mad. It only started doing this recently and I've no idea why. Does anyone know a solution to this?

 

Check your connected aplications if there isn't something suspicios that might cause this problem.

 

Thanks. I've revoked Access to all but Facebook. I'll wait and see how this turns out. If successful I'll introduce each one until the problem starts again so I'll know which is the culprit.