Why won't my cat stop scratching?

[MissisBoote]

I have two cats, both regularly de-fleaed using activyl.

My girl cat just won't stop scratching under her neck, so much so that she's got a few little bald patches where her fur has come out.

A few weeks ago she had a cyst that burst under her neck and as it was healing she kept scratching at it (could it because it was itchy as it was healing?). Could she have just got into the habit of scratching?

The boy cat shows no signs of fleas.

No sign of any flea dirt on withe cat or on their bedding when they get up.

Any ideas?

Sorry - meant to mention that the cyst was from a cat bite. Not sure if that's relevant.

I'm wondering if she's been getting into fights and that's causing her to scratch.

I know with grooming it produces endorphins so the cat can end up almost addicted to over grooming. My cat has a very well groomed bikini area!
Can you put a cone of shame on for a few days to break the routine?

If there's no flea dirt and only one cat scratching, I doubt it's fleas.
It could be where she's healing as you suggest.
Does she have a collar? That could be irritating her.
Or a tick, although I think you'd have spotted that.

No collar to irritate her.

She doesn't seem to be in any pain as she's happy to be stroked under her chin and lifts her chin up so you can easily see under there.

I think I'll keep an eye on her and maybe take her to the vet.

She does groom a lot compared to her brother. This morning she's groomed herself for about 15 minutes out of every hour.

Would the activyl work on one cat and not the other?