I don't understand the way the vet is getting a urine sample. I've been told for a urinalysis what really needs to be done is the vet takes a sample directly from the bladder with a needle? That's how my vet would test Max's urine (this is when they do the urinalysis at the vets or send out to a lab). With an experienced vet–it isn't painful. Also--if Max had just gone potty--and his bladder was empty--they would sometimes have to confine him there at the vets in a kennel and wait for his bladder to fill up before taking any with a needle. This might take a a couple of hours to get a good sample.
That also struck me as odd that the vet didn't draw direct. It sounds very serious I know how you feel. I hope he gets better soon!
Put the nuts in a cupboard with a padlock and a safe combination lock on them?
Nothing is sacred with a basenji around!! My mum used to have to put up the trash can as my B always ended up getting into it right after we closed the front door to go out.
I'm no expert but here is a link to a site that may help you identify what is wrong with him:
Quesitons you can ask yourself:
Is it only in one particular season in which this is happening?
How old is your dog? Is he fixed? - could be hormonal?
Changes in the dogs food?
Changes in what kind of material he sleeps on / does he wear anything like a doggie blanket now that he didn't before?
Is he itchy mostly a few hours after his bath?
If you think its allergy, try eliminating possible things from his environment one at a time to work out what might be contributing to it.
When my basenji was two I recall she had a few bumps, chewed the top part of her tail bare and had dandruff. We cured most of it with finding the right shampoo for her skin type to use. I think part of it may have been hormonal.
My Basenji also growled when woken up or moved from her warm spot. Didn't have a food problem though.
I've once seen her wake herself up from a doggie nightmare, she even snapped in the air a few times before she awoke.
The only way we could persuade her to move without the fuss was with something she liked even more than her warm spot like a treat or the heater.