Cat excessively licking his leg

Hi all. First post on here. I did do a search but didn't find exactly the problem I'm having with my cat.

Our cat, Karl, has been excessively licking one spot on his right front leg. To the point where it is very raw and red looking. This has happened once before (he was actually looking two spots on his right front leg, slightly different area then where he is currently licking). The first time, the vet gave him a shot of cortisone and a shot of antibiotics since it looked like he was starting to get a skin infection. Seemed to do the trick, and it started looking much better immediately (and he stopped licking as much). Well, it's been a couple of months now, and he has this new spot going again. Took him to the vet yesterday. Vet gave him another shot of cortisone, and wants to put him on this oral medication called Atopica - one dose every other day - for the rest of his life. 

I'm just looking for some advice or some confirmation that this is the right path? I hate to put him on a medication for the rest of his life if he doesn't  need it! Not to mention it costs $40 for enough to last us a little less than a month. I asked the vet about trying to change his food to a hypoallergenic one, and he didn't seem to think it was that great of an idea. Karl (and are other cat) currently eat Purina Complete Cat Chow. 

So, any ideas? 

Thanks in advance!

Welcome! Your poor Karl sounds like he has allergies. Usually when this happens I start with looking into their diet first and foremost to see if I can clear up the problem that way. It is very possible the Purina Cat Chow is the culprit. If you are interested in looking into a new and better diet, please bring up a new thread in our Nutrition Forum. Here is a great nutrition resource that will be good for you to peruse. Good info. on diets. (not just for raw! ) http://www.thecatsite.com/t/240809/raw-feeding-resource-thread It could even be an environmental allergen but I bet it is more due to an ingredient in the Cat Chow. I would start there! for Karl.

He may have a skin infection from moth eggs etc.

Try to gently wash the area that he scratches with water.

Hello, I was looking on sites to see why my cat is licking her legs and came across your question.I didnt notice how long ago it was put up.

   First thing is get off anypurina foods its garbage and absolutly NO nutrition.If I told you what it was made from you'd get ill. Find a food with no corn,wheat, basically fillers(purina 95% corn) cats need meat! Always read your ingredients and make sure real chicken, or the meat source desired is the first ingredient. Possibly the second also.

   Anyway I took my cat to the vet for leg licking, did blood work said allergy, ok so that was a while ago. She stopped (I thought seasonal allergies) Then a friend of mine who is a vet tech came by saw her legs ,checked her eyes and said her eyes were clear but sounds like Hyperthyrism, but shes on an exceptional top quality food  (HEALTH EXTENSIONS compare ingredients)  but your kitty is on purina thats why I would try food changes first, so honestly for you I would definetly stay away from supermarket,walmart etc cat foods most are toxic. and look into a better food iams ,eukanuba, no real meat its garbage also, look up catfood recalls or go to catfood advisor it may help u alot.I would change foods first and see if there are any changes in kitty...Hope I helped,Diane