Don't run from dogs, they're predators, even if they don't want to hurt you, their instinct is to chase. If you're afraid of a dog or think it wants to attack you, try to stay calm and walk away, don't look at it either. Dogs are mostly bluffing, even when it looks like two dogs are fightings it's noisy and impressive but most of the time there won't be a drop of blood. There are idiots around my neighborhood with a really aggressive labrador, it runs to you growling but if you don't move it stops. People who run from it however, have been bitten. That dog may be a pitbull, it's still a dog. I don't even know how it chases you or if it actually bit you but it might even just be playing, sometimes it's hard to tell.

Once again proving that the only things that smell fear are the things you include in your escape plans.