Itchy dog - any ideas?

[ThisIsACoolUserName]

Can anyone help shed light on why my Border Terrier is SO itchy, and what I can do to help her?
She's been itchy - to a greater or lesser extent - for her entire life. The vet has previously prescribed a flea collar because she's apparently extremely allergic to flea bites/flea dirt. However, I've never seen a flea on her and I inspect her regularly, and the flea collar had little impact. For about a year, she's been on Nutri-Paw All Itch Immunity Treats and they've made a big impact - until about a month ago. Since then, she's been FRANTICALLY itchy. She's biting and licking her back legs, feet, tail and sometimes her bottom. She'll wake me up in the night doing it and sometimes wont stop until I (gently) hold her head and it sort of snaps her out of it.
We've wormed her recently (an over the counter tablet though, not a vet-prescribed tablet - is it going to be strong enough?).
I wondered if she'd picked up an allergen on her fur whilst out on a walk, so I've washed her. I've combed her - no evidence of flea poo. Her skin doesn't look sore anywhere - no red or scabby patches.
She does have mild arthritis, and I was thinking about the itching being her way of trying to deal with soreness, but she's in really good shape at the moment and zipping up the stairs without any lameness at all.
Has anyone else had a dog with these problems and found a way of helping them?

Is it the food? Chicken sensitivity is very common. My Lab is on a fish-based diet.

Coconut oil or salmon oil either in food or massaged into coat is worth a try.

I’d say possibly food. Our dog changed almost overnight after changing to hypoallergenic food.

Cushings Desease, get blood test, cortisone helps

Our dog was like this, after a check at vets to see if anything more serious was going on, we changed his food to Seven and avoided chicken and he's been fine since.

Sounds like she needs a trip to the vets, could well be allergies, may be seasonal. My dog is itchy in the summer months and she has cytopoint injection once a month, totally stops the itching.

We did allergy testing for ours as he was forever getting ear infections and scraping and licking and he is allergic to beef, yeast and dust. Mildly allergic to a few other things. He’s been a lot better since we switched his food but he still licks his toes which I think is habit. I add organic apple cider vinegar to his food and rub it (diluted ) over his feet and that seems to help.

Vet here.

Food allergies present before the age of 5 so unless you changed her diet a month ago, unlikely.

As signs worsened a month ago, it's probably a pollen/ grass allergy, given the time of year.

She needs to see her vet to look into this and they'll probably give some anti itch medicine like Apoquel and treat any skin infection with antibiotics or a medicated wash.

Vet nurse here , you/she may be one of the unlucky ones with an allergy that you will never find the reason for.
I would go to vet and ask them to check her anal glands sometimes if they are very full the dog can feel generally irritated all over and they will bite around bottom ,legs and feet.
The wormer is probably irrelevant at the moment but show the vet what you bought and they will advise.
She may need to be permanently on meds to control her allergies sometimes apoquel tablets or cytopoint injections can greatly improve such situations.
Both are quite expensive but you can get the apoquel from an online supplier using a written prescription you buy from your vet.
If you decide to use an allergy diet go for a poultry free one stick with it and give nothing else whatsoever if the diet is going to work it takes about 6 weeks to see a difference.
Avoid shake and vac type products , plug ins , febreze type sprays ,keep her environment as simple as possible.
Sadly its very common to see dogs with allergies and it can be a case of hit and miss to find the best thing to control it , summer is usually the worst time ,similar to a person with hay fever type problems.

We dumped the chicken and beef - duck Nutriment only in this house
Plus allergy to grass/pollen is common so we bath her every week

Thanks so much for the replies everyone, they're really helpful. I'm amazed to hear about dogs with chicken allergies, that's something I've never heard of. I'll book her into the vets and look at her diet.

@florriegirl Do you get your cytopoint via insurance? Reason I'm asking is we have got the injections for the past year and my insurance has gone through the roof £149/month my renewal came in at 😱

We had an itchy welsh terrier - stopped wheat/grains and he was fine after that.

My GSD is like that. She’s allergic to chicken so is on mainly fish and duck. She’s also on Apoquel which helps a lot….without it she’d scratch herself to bits and go bald.

My dog has yumega itchy dog ( a fish oil). I would have said he had a low grade itch problem.
The Yumega really helps the itch, plus he has a gorgeous coat.

Another vote for cytopoint, Westie gets a jab every 8 weeks or so and is on low dose steroids every second day as well and absolutely no itching now.

Thanks for the recommendations for cytopoint, Yumega, and some diet pointers to explore.
Poor thing. She's my best mate and it must be driving her crazy feeling like this 😌 Hopefully I can get her sorted.