Young dog, itchy feet now under the weather

[Zirach]

Hi guys, my year old small terrier x has been suffering with itchy legs for the last month. Vet suggested half a puriton tablet (due to his size) a day and bathing legs with malaseb (I think that is how it is spelt). His is a white dog and pink skinned. The tablets have helped bring his skin colour back to pink (it did flare up quite red) around his eyes, but after another malaseb wash last night he is very withdrawn this morning and not his usual self at all. He is eating (just) and toileting ok but seems uncomfortable around his back legs. He has a small rash (almost like a red dirt) on his belly.
I have heard of harvest mites especially becuase of his small size but vet seemed to think it was a general allergy.
Before I take him back, I wanted to check on here if anyone has any similar occurances/knowledge of this. Whilst I trust my vet, they do like to wack up the prices and I was wondering if there was anything else I could try.
As a pup he was on james wellbeloved food, he has been having a supermarket brand food for the last few months and I will be changing back to james wellbeloved as it is hyperalergenic and this might help?

 

[Aru]

If you are changing to a hypo allergenic diet make sure its an exclusive diet.No treats,jusy the set amount offood and water or you are wasting your money.These diets also take around 8 weeks of a exclusive diet in order to rule a food intolerence in or out so no quick results overnight either im afraid.

Being up to date for fleas and parasites is also very important in these cases so regular use of a advocate or its equvalent would be another good idea.As this can help rule out a bite allergy.
Allergics are very common.But there are a hugh amount of causes so they are often quite difficult for a vet to work up and give a specific diagnosis as its a matter of excluding the common issues.So a number oif different tests can be taken to rule different things out but its not a quick and easy cure in a lot of cases.This could be a longterm issue but hopefully ye will be able to find a cause.
How long has he being itching?

 

[Zirach]

Thank you so much for your helpful advice, I am very grateful.
He has been noticably itching for the past couple of months but it has got worse this last month. Since we moved house really. We have carpets now whereas previously we had laminate flooring, also where we now go for our walk is a meadow with rather long grass whereas previously it was cut lawn. Do you think these could be a contributing factors? Thanks for the advice re the food, he is frontlined regulaly and wormed but he is due (flea) so will do this tonight. He did get several tick bits a few months back whilst we were on holiday in Wales, we tweezered them out and frontlined so I dont think this could be anything to do with it - I certainly couldnt see any when I have been bathing him.

 

[CorvusCorax]

He might just be reacting to the cheaper food? Just a guess though.
What breed is he? Mine gets 4 piriton a day although he is a large breed.
Could be the carpet also. Also discount a cleaning product or washing product, especially anything containing pine, it is being recognised as an irritant (says she who lives in a pine forest )

 

[Zirach]

He is a miniture poodle x yorkshire terrier (although looks like a scruffy jack russell) so quite tiny. My mums choc lab has 2 tablets a day. I dont think I use anything that contains pine but will have a look, thanks