puppy biting

Don't get me wrong. I like dogs but on my terms. I am a human and they are animals. I'm allergic to them so I prefer to keep them at arm's length unless there is somewhere I can wash my hands straight after stroking them.

Usually I can keep dogs at a distance by not paying them any attention or staring them out but I have to regularly visit a house were a puppy isn't being taught how to behave. Every time I walk into the house it jumps up and bites my hand. At the moment it doesn't break the skin but it's getting bigger and stronger every day. I know in dog terms it's protecting it's pack/territory but it can't bite me every time it sees me.

So here's my question to all you doggy people. How can I stop it? I've spoken to the owner but she says he's 'only playing'. It's not a place I can stop going to. I don't want to do anything unpleasant to the dog but I need it to know it's place where I'm concerned like their older dog does.