secretions after brushing my cat

Question
Hi there,

I've noticed that, after brushing my cat, small clumps of fur accumulate along his spine. They seem to be oily and after a couple days, they dry up and can be pulled out. He does regularly have dandruff and he has feline herpes. I'm assuming his sabaceous glands are a bit overactive. He loves to be brushed but his back is rather senstive afterwards due to these clumps. He has a swollen gland near his tail that's been there for a while and he tends to bob his head and make licking movements when touched there or in that general area. My questions are, are these clumps/secretions normal, and is it normal for him to be so senstive on his back and rear area? (He's not necessarily irritated when I pet his back, but he does sort of "shiver" and do the head-bob and licking thing)
Thanks for your time!
Jackie

Answer
This could be the result of an allergic problem resulting in sensitivity of the skin. This "stud tail" is nothing more than an enlarged oil gland on the tail.  If he is not neutered, sometimes removing the testosterone source may make it diminish in size. I doubt that it has anything to do with his herpes.