Is there any home treatment that I can use to treat my dog's allergies?

Now you know why the purebred dog fancy sneers when some uninformed person touts the "healthier hybrid" dribble.  

Have you looked at his food?  I know dog owners who would have their dogs skip a meal rather than feed Iams.  Go to a pet food store and find NutriSource, especially their PureVita or Element brands. It's a more expensive food but it is well made and uses a single source animal protein, which can help a dog with allergies. 

The issues with 'allergy' medication is it covers up the reason for the allergies rather than resolve the real issue and although  cytopoint  can be used 'safely' with any age of dog, it is just covering up the reason, but medication is chemical and does reduce the dogs immune system resonse/affectiveness and it is the immune system that protects and fights illness, injury and the 'catch all' often used  term 'allergies'

Convenia is used in dogs to treat skin and soft tissue infections as well as UTIs and Claro is a prescription ear anti inflammatory steroid solution...and long term anti inflammatory and steroids wreck the dogs kidneys as well as the immune system.....so the dog has no natural immune system to fight 'allergies'

Iams is the cheap supermarket brand made by Eukanuba.........so my advice would be to feed a better quality of food as a starting point.... Iams is often associated with skin and ear infections because of all the junk ingredients in it ( and I worked for Eukanuba so I KNOW what junk goes into it)

If you are bathing your mix more than every couple of months, then stop as you are stripping its coat of all the protective oils, again causing dry skin, skin irritation and the immune system is fighting to reproduce all those natural oils and ANY shampoo residue left because of lack of correct rinsing will also irritate the skin........groom as in brush its coat daily instead.

I have not used fleas/tick/wormers for 30 odd years, I use 100% neem bark.leaf powder half a teasp daily for a week, half a teasp every other day 2nd week, half a teasp once a week for the 3rd week then half a teasp once a month after that prevents and kills ANY parasites and the benefit of neem is it also boosts the immune system... and as an external coat finisher 100% neem oil, a small coin sized amount on your hands, rub into the coat to protect it once a month, it has a weird smell when first put on but it is great, good for the dog not wrecking the dog so you get used to it.

The groomer might be getting water in his ears during the bath, that would certainly cause ear infections etc.