dog has sores around his mouth?

Hi all. Ive got a 2 1/2 year old presa canario/pitbull cross and as of recent he has been developing sores around his mouth that occasionally bleed...... They are very dry looking. Also it broke out a bit on his side and he is constantly licking that spot or scratching his side up against the couch. We switched his dog food a couple months back and a friend of ours thought maybe it was a food alergie. We switched him to a good brand (IAMS proactive health.)
Ive posted a few pictures for anyone to look at. Please tell me what you think it could be and how to possibly treat it...

[TwoBitsMom]

I wonder if it could be his bowls....?  If he has plastic bowls, you could try switching to a stainless steel, glass, or good quality ceramic bowls.

[Misfits4Me]

Hello John & welcome......You need to see your Vet for a skin scraping...I'm afraid this is Mange! If left untreated, it can cover the entire body....

A skin scrape/culture will determine if this is either kind of mange, bacterial infection or ringworm.....Yes, it could be an allergy, but you you don't want to mess with any of the first mentioned.....It's much easier to treat these conditions before they spread......

Mange is commonly found on the muzzle...Now, you say there's a spot on his side.....You DO NOT want to guess with this or try to treat it yourself......

Get him to a Vet ASAP before it gets worse.....Please, come back & let us know what you find out.....Good luck, Karla

[TwoBitsMom]

I initially thought that your dog had issues on the SIDE of his mouth.
But as Karla has pointed out, and after re-reading your post, I understand that it is the SIDE of his body as well as around his mouth.
With that claification, I certainly do agree with Karla, and you should get your dog in to see your vet.
If this is spreading to other parts of his body, it would be in your best interest, as well as your dogs, to get this professionally diagnosed as soon as possible.
Connie
P.S.....That is a great photo you took.