My cat has lost a big chunk of fur from the back of his neck. Help!

This is my 1 year old cat, Charlie.  He came home the other day with a big chunk of fur missing from the back of his neck. My first instinct was that he'd been in a fight with another cat.  I put some pet safe antiseptic on it initially but after a week it doesn't seem to be healing. We have a younger cat who had ringworm when we first got her. I think we got that under control as I haven't seen anything on her in months (or on him). My husband thought this area on his neck might be ringworm but they are usually circular.  I would normally take him to the vet but we have recently moved across the country and we don't have any income here yet so things are tight.  Should I just keep bathing it?  As you can see in the photo, his coat is quite shiny though he has been dropping a fair amount of fur around lately as well. He did a big puke after dinner today and I'm starting to worry something more sinister may be going on. We feed him with one of the more expensive cat foods. Any clues or advice?

PS Yes, I know the best thing to do would be to take him to the vet but spending $70 to have a vet tell me to keep bathing it isn't really an option at the moment unless you think it's urgent - my kids and I dote on our pets.

The easiest thing to assume is that he was injured in a fight with another cat.  If that's the case, keep your eyes open for other sores/abscesses around on this body.

A second possibility is that another male tried to mate with him.  Yeah, it happens, usually it's a display of dominance.  That is the classic location for the bite marks from that kind of experience.

It's possible he just caught it on something sharp, like a nail in a fence or some such thing.

If the fur came off in one clump, that usually indicates an injury.  But another possibility is a ringworm infection.  It doesn't look like that, but it wouldn't hurt to treat him with an athlete's foot cream, since he probably can't lick it off right there.  Just rub it in, so you don't leave any on the surface. 
 

Thanks for the reply. I think your hunches are much the same as mine though I hadn't thought about the mating thing. Lol. Maybe that would explain why Charlie is such a cranky cat...lol. I've had unaffectionate cats before but this boy is something else.  He gives about 5 minutes of affection per day, usually at bed time and his affectionate moments are sooooo over affectionate, you actually start to feel smothered.  This isn't something recent though.  He was like that at the shelter when he was 10 weeks old too and while I wanted a snuggle puss, my husband liked the idea of a more independant soul. We love him all the same though and it makes his small affectionate moments all the more meaningful.

I'll keep putting some cream on just in case it is ringworm. I'm sure it won't hurt.
 

I can't say for sure just from the picture, but a competant vet would be able to give you a better idea. My first thought was that it looked like ringworm to me, but if he goes outside it's entirely possible he had an altercation with another animal. Has it spread at all or gotten any worse? Did you notice a balding spot before he came in with the sore? Ringworm starts off slowly with a bald spot that starts getting pink.

If it doesn't start to look better soon or it gets any worse, I would just bring him to the vet.

Hi
This looks exactly what has happened to our cat ( for the third time now!) Did you ever find out what it was? I just assumed either fighting or getting it hooked on something too.