You can start by giving it a good brushing and if it continues from there try bathing and sulfadine on the itchy spots if it persists contact you vet and ask for advice.
Examine the dog's fur for fleas. If found, apply a product that kills fleas. Apply an antibiotic cream to any broken skin. Give one Benadryl tablet to decrease itching.
It is common for miniature schnauzers to develop skin irritations that appear like tiny pimples. If your dog is scratching, bathe them in an oatmeal based shampoo.
