my male gets this from time to time… it goes away, usually after a good bath so i’ve ruled out hyperpigmentation, it’s not smelly so that generally rules out yeast, no fleas so not flea dirt… i just assume it’s from him licking (similar to tears causing those dark tear stains). i brought it up once at the vet and she rattled off a bunch of things, most of what i’ve written above but wasn’t concerned. i stopped worrying about it. he’s got it now - on one side more than other and it correlates with the opposite side that he usually sleeps on, which supports the possibility of licking.
anyway, quite the word dump… any of that ring true for your boy?
