Question my other half insists that I ask.

Sounds like vitiligo - try http://en.wikipedia.org/wiki/Vitiligo as a starting point for research.

Mick.

Whatever it may or may not be, you should discuss this with your GP. We cannot offer a diagnosis only comments from our own experiences.

There is a fairly common condition that exhibits these symptoms. I cannot recall the name for it but a friend of mine suffered from it. The cure was to rub anti-dandruff shampoo on the skin. This cured it for my friend. ISTR it was a sort of skin fungus. Sounds mad, but it was true.

My immediate thought was "vitiligo"
It's nothing to do with diabetes, although may be an auto immune response. I know a couple of people with it. Neither is diabetic.
You need to be very thorough with sunscreen
By the way it was always what Michael Jackson said caused him to change colour. It's certainly possible. I did once see a "black" man who was mostly white with just a few brown patches.

Psoriasis is linked with diabetes.

I have white blobs on my fore arm that don't flake, but the patches of psoriasis on my scalp do. Just go to the doctor maybe he can give you some pointers/help. I'm also getting tiny patches near my hip bones which i think might be psoriasis too.

Good luck with finding out!there's nothing wrong with doing the doctors head in with questions (also if it is psoriasis, one ointment might flare it up, another might do nothing and another will be great, so it's trial and error, took me years of trial and error to find the right ones)