Hello:
It is very possible from the symptoms that you have given that your little one is showing signs of thyroid disease. When this occurs it is very common that dogs will lose their hair and scabs or waxy crusts will appear. These "scabs" have a very distinct mousy (awful) odor.
Your vet will be able to take a blood sample to determine if this is the cause and then prescribe medication that will have to be taken for the disease.
If this isn't the problem (I believe that it is) then he could have begun to develop dermatitis (allergy induced), demadectic mange, or exzema, ie. Your vet will be able to do a skin or cell scrape to examine for the above possibilities.
To aid in the regrowth of hair and only after he is diagnosed by his vet, you can bathe him with a mild oatmeal shampoo, such as Aveeno.
The bottom line is that he really needs to see a vet in order that he have an evaluation done by him to identify which of the above problems he is experiencing. In order that he can provide the proper treatment.
If this information has been helpful to you then please do ACCEPT. Let me know if I can help you further. Positive feedback is always appreciated.
Breeder & Rescue
Breeder of Small Dogs-Poms, MinPins, Yorkies,