Any ideas about red patch appearing over one eye brow on an other wise healthy cat ? He has always been a very thin in fur over his eyebrows more so than most cats but vet says its just him. I know this is an area that has glands doesn't seem to be rubbing any more than cats do when they are being friendly or scent marking. Have checked his ears fro mites all clear but have treated with thornit just to be sure also and rubbed some carefully into his brows. Its not sore or itchy or scaly just red when the other isn't and it is usually normal skin colour  Any ideas before a vet visit please ?

This is usually an allergic reaction of some sort and isn't uncommon, the location is very typical, and can appear all of a sudden. I have a 13 year old Exotic who suddenly got this a few months ago, above both eyes -I've not been able to find what is causing it , not for certain anyway (could be that I started giving the cats a bit of boiled fish a couple of times a week whereas before they only got  raw meat), but it's not bothering her and has not got worse either, so I have just left it.

Allergies ! I hate them could be fun tracking that down thank you Marianne. Btw this is the same cat who had cat flu as a kitten and has had problems with being sick Vet has checked him out including xrays and concluded allergy to his food offered hills sensitive dried.
Declined that to try raw ( not that the vet was happy with that ) but  have discovered if he doesn't have dried food he isn't sick ! he eats far to quickly and throws it up :) little  greedy guts  .