My Merry started itching at 3 months old and I don't think hers is SM. It is mostly around her hind legs.
I had tried all sorts of foods and couldn't find what she was allergic too. She scratched so much she would wake me up in the morning because she was shaking the bed. Her nails were shaving off the ends of her fur, so her hair remained short, even as an adult.
I finally admitted that my hit or miss approach wasn't working. So next I
talked to a vet who told me last November to give her 1 tablespoon of children's benedryl twice a day and that helped. She didn't scratch, but I didn't like the long term health implications. So next, I took her to a dermatology veterinarian this past May and she started her on an IVD dry dog food diet of rabbit and potato food and the scratching stopped.
Merry is now 2 years old and her hair is growing into a full coat for the first time ever. Now Merry is on a very strict food diet.
Charleen and Cav's: Pippin (ruby male), Merry (b&t female), Luke (blenheim male) & Jolly (tri male puppy)