A week ago, last Tuesday I spotted clumps of black fur all over the place - not spotted anything untoward when I left for work but walked in to this, and a large oval egg sized bald patch on his back. Took him to the vet, who suspected he may have been bitten but not punctured the skin and this had induced an allergic reaction, presenting as eczema, so two injections and a hard collar to stop him licking it, to be worn for two weeks although improvement may be seen after a week.
The area scabbed over and then the scab came off on Monday, and now he is able to scratch the spot with his back foot So it's getting a bit bigger, not better. More bits of black fur but not as much as at first, and another fresh scab. His behaviour Tuesday night was plain weird! I think it must have been incredibly itchy, sore or both, and he was leaping about on tables and beds, licking as best as he could, scratching and shaking himself, sitting on my lap which he very rarely does normally, and just wanting to be close to me, all night and all evening.
Debating what to do now - vet again? I've posted a pic of his back today on FB for anyone who'd like a look