My Dalmatian is a diabetic puppy…or is he?

It's hard to say without seeing all of the blood work and diagnostics run by your veterinarian but diabetes is usually a pretty obvious diagnosis so if they believe it is diabetes, it probably is. Still, 1 1/2 is VERY young for this disease. Most dogs don't get diabetes until they are at least 6 or 7, even though they are type I diabetics. So I would be looking for an underlying cause, like a disease such as chronic pancreatitis that can affect the pancreases ability to secrete insulin or other disease such as acromegally (over production of growth hormone) that can result in insulin resistance in a dog. If your veterinarian hasn't already done one, I would recommend an abdominal ultrasound to start looking for more answers.