I took my old cat to the vet as he went bold under his tummy and some parts of his hind leg, They did not look sore or anything like that just bold, The vet thought he was allergic to plug in air freshners which i have had for years, sometimes for some strange reason they just become allergic, without doing tests she could not pinpoint what the allergy was to,I took out all the freshners.....but most of all i put him on a senstive diet for cats ( hills ) it worked but it does take six weeks for all the additives to come out of there system..... if your cat is not in any distress and is acting normal i would try that, but if you know there is something not quite right with puss take him straight to the vet.