Skin issue

Question
Dear Sandra,
I've noticed a strange area of skin on our female black-and-white hooded rat, adopted, unknown age(we're guessing around 2). She's happy, hungry, and it doesn't seem to make her itchy, but she has a bald patch with a small black ring on the skin near her shoulderblades. The ring is about 1 cm in diameter, maybe less. As I said, the ring is black! Like, skin-pigment black, not rotting flesh black. The skin seems to be unbroken, and it doesn't look like she's been scratching. I've seen ringworm before, and it does not resemble it at all. The skin around and inside the ring is bare, and there's no redness. Any idea what has caused this?
I wish I knew exactly when it emerged, but I don't live with the rats full-time and my boyfriend can be kind of clueless about this stuff.
Any help would be greatly appreciated!
Best regards,
Steph

Answer

The black ring you see can be just that...pigment...and if fur grew back in that area she probably has a black cirle of hair there. The question is, what made her fur come out in that spot to begin with.
IT could be anything, from hormones to excessive grooming, but again I am pretty sure (as per the visual I have in my head) the black ring you see is the pigmented area where new fur growth will be and since the fur is black ,the pigment will be black too. Hope that makes sense.

Is there a way you can take a photo and send it to me at Sandyscrittercity@yahoo.com?