Can you give cranberry juice or cranberries to dogs is you suspect a UTI?

I'm not sure if my 9 month female chihuahua has a UTI, she seems to be drinking just fine but I noticed when she pees it crusts over on her hoo-haa and she's a little sensitive in that area. She doesn't have a vet appointment till the end of this month, so I don't want to make 2 appointments if I don't have to. Can I give her cranberries or cranberry juice just in case? I know that it fights UTI and bladder infections in humans. Please help...