My 16-year-old cat, otherwise healthy, has a chronic skin condition, linked to swollen hind lymph glands. The glands notably swell up in rhythm to the severity of the skin condition around his lower back/sides and tail area, confirming the two are linked. The skin conditions manifests as a dry crusty series of bumpy scabs on his skin, which I can tease out with a fine-toothed comb. I do that each day or the affected area would soon scab over. He constantly grooms himself in that area, to the extent that he bleaches his grey tabby fur orange, and can also end up with a fur ball. He's out most of the day but I bring him in during the night and from his litter tray his bowels are functioning normally. I have however used Katalax to see if he was constipated in some way due to ingesting fur and this was causing the problem. After 3 years of taking him to a vet I still don't have a confirmed diagnosis! They started off suggesting worms, then flea allergy, and seem to be sticking to the latter, despite this cat not realy having much evidence of fleas, and there's no fur loss/reddened skin. They'll run a flea comb through him and do not find any fleas or dirt. He does not scratch, only groom, and the condition continued while using Frontline. My other cat can get fleas, this one noticeably does not. I have occasionally looked after hedgehogs and one may have a fungal infection causing it to lose spines, and such a hedgehog will not have fleas. This prompted me to ask the vet if it could be a fungal infection of the cat's skin, making the hind lymph glands overproduce cells to fight what the body sees as a local infection, but they seemed doubtful and suggested it would need £300 worth of culture and biopsy tests which may ultimately prove inconclusive. The cat used to live outdoors as a sort of street cat until I adopted him 3 years ago. At my suggestion I had a blood test done for FIV, after reading that it can cause swollen lymph glands, but he was found to be clear of all cat viruses and his liver and kidney functions were fine. The vet even suggested doing that again, so we just keep going round in circles. Other than this he seems a healthy cat, and has put weight on this winter. What can be causing this problem?