I dont know that I would bathe him if he isn't dirty. Bathing dogs tends to dry out their skin and would probably make him more itchy. If he ends up being filthy, dawn dishwashing detergent is best as it's mild to skin and fur and it has no harsh chemicals like pesticides.
I have a dog who has food allergies that can result in skin issues. I've never heard of using Ivermectin for this purpose? Ivermectin is for heart worms, is it not? Can you explain more? We use one source carb/one source protein dog food and this takes care of the problem.
I also would not use Dawn or any other dishwashing liquid. I would call my vet and ask for a recommendation for a mild puppy shampoo.
When we got one of our dogs as an 8wk old pup, he had horrible skin. He had scabs all over and itched like crazy. He didn't have mange but the vet said it was some type of skin infection. He was on oral medication as well as we gave him a bath three times a week for two weeks. The shampoo the vet gave us was Malaseb Theraputic Shampoo. The active ingredients were Miconazole Nitrate and Chlorhezidine Gluconate. The oral meds and the baths cleared up his skin and he was a normal happy puppy after several weeks.
I don't see why you couldn't use a topical human anti-itch cream or lotion provided you ensure pup isn't allowed to lick any. I know plenty use Benadryl for allergy related issues. A vet may be able to provide you with an oral medication or supplement to help, depending on the root issue. Others find fish oil liquid pills help many skin issues.
I had a lab/ blood hound mix that had a TERRIBLE skin rash all over his belly to the point is was bleeding from him chewing at it. The vet gave us KetoChlor medicated shampoo, I also went to walmart (or a pet store) and got cortisone pet Spray that helped stop the itching. You can also use neosporn on the really bad areas (just rub it in well).
This really helped clear up the rash fast!!!
And my poor dog has sensitive skin, so I only use OATMEAL shampoo when i wash him once a month to help his dry skin out, and you can use the cortisone spray anytime you want when they are itchy
IVERMECTIN can be deathly for German Sheps, Border Collies, Australian Sheps, Greyhounds and a couple other breeds.
What kind of food you feed? Some dogs are highly sensetiv against soy, wheat and corn, please read the lable on your foodbag
I had good luck using an equine tea tree oil shampoo. This dog had a terrible rash for months and we tried everything. I had the tea tree shampoo on hand and decided to try it. ONE shampoo and the rash disappeared. Later on I read that dogs don't tolerate tea tree oil. I'm glad I read it AFTER I shampooed her.
I have never heard of ivermetin for food allergies. I know it works on some skin mites?