Why does my cat nibble her tail?

Hi Elaine,

I have a cat - try to bear with me on this one. She's four and a half years old, in very good health, eats Iams, and is de-flead regularly by the vet.

But she doesn't go out - not through the lack of trying - and instead keeps nibbling the base of

her tail and down towards her left back leg.

She's going bald. She has a

season even though she's been spayed. I think I've got a weird one here.

I have thought of taking her to the

vet, but it seems too petty on such a small matter.