Took our dog to the vet today, I've been away at my parent's for the last week and when i came home a couple of days ago noticed he had started licking at a patch on the top of one of his back legs (near his tail area). It was getting a bit yucky and like there was pus underneath the skin so I thought maybe it was a hot spot (as Golden retrievers/labs are prone to getting them).

Anyway the vet said it's most likely a flea issue and asked if he had regular flea treatments, um no ( ). I just don't understand how he can have fleas when there have never been fleas on him. Surely I would have noticed if he had a flea problem? He's only been licking that one spot, I thought if he had fleas he would be itching and scratching all over, or at least in more than spot. I had a close look at his coat/skin tonight and can't see anything. He is a bit grubby but i would have expected that since he digs/rolls around in the dirt and goes swimming in the river every day. But definitely no fleas jumping around and nothing I can see that would be flea dirt (unless I just don't know what I'm looking for).

I feel like a terrible dog owner now, the vet used this almost condescending/humourous tone after I'd said he doesn't get flea treatments because we've never had a problem with fleas and now I feel really bad..