When my rabbits shed, they seemed to get a bit more flaky during that time, so I agree with Bam, that it might have to do with the shed. So if this clears up after the shed in a few weeks, then you’ll have your answer. But it is something to keep an eye on.
One of my rabbits would get dry skin and lose hair but more so in specific areas — her cheeks, ears and neck and shoulders. She was tested for mites etc, and all was fine except for the test revealed it was a type skin inflammation that was typical for allergic reactions. (I can’t remember the name of it). I use retin-a on my face and so I thought it might have to do with that — was more careful about cleaning my hands thoroughly after application and I avoided rubbing my face in her fur. (which I loved to do!). That ended up not being the culprit, but it can be….so I’m just mentioning it as retin-a and other topicals could possibly cause issues with our rabbits if we pass it on via contact.
I then heard about hay allergies in rabbits — typically Timothy — but after talking to a vet that also was an expert in hay, he mentioned that it most likely had less to do with the hay, but a common weed that grows with Timothy, and that weed can’t always be fully taken out. It’s not harmful in a digestive sense, but it can get mixed in the hay and in the Timothy pellets. This then can cause an allergy. I changed the hay to Orchard and used an Orchard base pellet. Her skin cleared up after that. So I think that was it!