skin problem

hi,new to the site. i have a dog and he has been suffering with small bumps on his skin on his side,he has scratched so much his fur started to get patchy. i shaved the area myself to have a closer look they are not red or flakey but do make him itch. i was feeding him on gain greyhound mix but my friend who breeds labs recommended changing his food for a less protien content so now he is on arkwrights mix. my question is does anyone have or had this problem? i dont bath him often as i thought that was bad for them, he is easily distracted from scratching so i dont think its causing him pain and probably does most of his scratching when he is alone. please help.
thanx

Hiya Simon sounds very much like diet I had this problem with Vinnie when he was small. A change of diet worked wonders, though he still has flare ups from time to time. I use Viacutan plus an oil which goes on the food. Origionally prescribed by my vet but I now get it from Amazon as it is slightly cheaper.
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If it's a food allergy probably best to feed a hypoallergenic grain free food   

How long has he been having the bumps for?

Sounds very much lke a food allergy. Suki was allergic to alot of protein sources when she was a pup but she outgrew them and can eat pretty much anything now. Venison is a good protein source for allergies. Have you consulted a vet about the bumps yet?

he started scratching about 3months ago but i couldnt feel or see them back then but in the last month i noticed his fur getting thinner in that area so i shaved the area and i could see them,they looked like the sting people get from nettles but since changing his food they have calmed down considerably.