Dog's collar rubbing

She hasn't got fleas or anything like that.
Basically she has had nylon, faux leather collars and a rolled real leather one. The problem i have is her collar irritates her when it's on a lot. I notmally have to take her collar off a couple times a day and give it a good scratch, her skin isn't inflamed or anything and i can get around 3 fingers in her collar (don't use it for walking - just id tag).
I can't really let her go without a collar as she is stranger aggressive so we need to be able to grab her quickly so has anyone got any solutions to prevent it annoying her so much?
(My parents don't like her having a harness on either even though she's my dog )

Thanks in advanced
There's probably a simple solution but i've lost complete concentration at the moment

vet check?

She has had a full check (got vaccined last week with a health check). He said it is likely the heat but it started happening a little when we had ice, then it stopped and it started again a couple of weeks ago.

Could it be an allergy to something on the collar? Is she scratching at any particular area, e.g. where the buckle/D-ring/tags sit? Dogs can have metal allergies like people, you could try a collar with plastic fixings and a plastic tag (Identitag do engraved plastic tags for about £4-5)

I didn't know you could get them engraved tbh, may look at getting her a cheapie to see how it goes (she used to have a buckle years a go and didn't have much trouble if any - hard to remember) but i had to get rid of it as it was when we walked her on her collar and the pulling kept lengthening it lol
thanks

I'm sorry, I don't quite get what you mean?

we had a staffordshire bullterrier in the rescue with a similar sounding problem to this.
In the end we had to order a special, extra squashy, super soft collar which fitted just right and did not rub in any way. He was also given some supplementation and cream to help with his sore skin.

Also we found.. sea water really helped. He started taking dips in the sea once or so a week, and with the combination of a new collar which did not rub, the creams and the ocean dips it cleared up in no time. Obviosuly, not all dogs like the sea mind!

Mine have theirs off in the house. For one thing, it ruins their fur, and they did occasional scratch at it. I wouldn't want to sleep in my clothes, so I don't see why they should ;0
Do you have a lot of people coming and going in the house? If she is nervous of strangers, can you not remove her before they come in?
Also, maybe a metal alkergy?

KRYLR =
She had a clip one before and we had to get rid of it as when she pulled on the lead the collar would lengthen.
When she had it we didn't have any troubles (if i recall) and i will see about getting her one as she is now walked on a harness.

TWILIGHT WOLF = Thank you i will have a look at that, have you got any links or brand names

This reminds me, Dog-games have some very comfy looking fleece harnesses on their website
http://dog-games-shop.co.uk/fleece-lined-dog-collar