Hair of the dog...or the bear
BBC
ASK A STUPID QUESTION: Quite!
As animals spend more of their lives in manmade environments, their predisposition to allergies increases. This is illustrated by the case of Siku, a polar bear at Lincoln Park Zoo, Chicago, that has developed allergies to, among other things, human hair dander.
Katarina Zimmer presents a TLDR, so I DR to the end. But the gist seems to be that living in sterile surroundings in proximity with humans has led animals to develop a reduced resistance to allergens.
According to her: We often think that allergies only afflict people, but a broad range of other animals can also develop them.
Well duh! That's because they have a functioning immune system innit? And, since they have a functioning immune system, why would we
expect them to be unafflicted by allergies?
That a zoo animal, or canine companion, has developed an allergy to human dandruff simply reflects an individual response following exposure to foreign matter. The same is true for humans with allergies to cat hair, for example, or even tree pollen for that matter. The point is that as an individual is exposed to a wider palette of potential allergens within their environment, the chance of them developing allergies increases; and some are more susceptible than others. None of this is remarkable or unexpected, and to imply that proximity to humans causes allergies in animals per se, rather than offering another potential allergen to a potentially susceptible individual, is misinformative at best if not outright disingenuous. I'm going to give Zimmer the benefit of the doubt in assuming she's simply an enthusiastic generalist with limited critical faculties.
What she may or may not have investigated later, if she did though I DR that far, is how much is known about allergies among animals in the wild? It's not as if it's something that would occur to many people, and it would be a sonofabitch to investigate for those to whom it did.