Sorry, I should have given more details.
My got my girl in October 2018 at the age of five months. She has scratched for England from the start. She came with some raw food and Purina Opti Start Medium Puppy. I was told it would be ok to change from raw, I do not have facilities to deal with raw food so changed her gradually to wet food but continued to use the Opti Start, she was doing copious soft poo. She is also very fussy which doesn't help. Eventually, I had her on Lukullus wet food and Arden Grange kibble, she was doing very well, eating it and putting on weight. In December 2019 she had eaten her breakfast, done a three mile walk, then late afternoon threw up bile. Refused any food until the next afternoon when I tried her on boiled white fish, that was ok. Tried some more later with rice and seven hours later the lot came back undigested. Vets next day, the vet examined her and said she wasn't uncomfortable and gave an anti sick injection. She did eat boiled white fish or boiled chicken breast but was sick again after a couple of days so took her back, different vet on duty and she was dosed up with antibiotics and omeprazole, told to use Purina en wet food. She was very hungry by then but the whole lot came back all over the carpet and was told to cut the amount of antibiotics etc. and put her back on boiled food. Eventually she was passing just mucus and gas. Nine days from the start they had her in for xrays, scan and bloods. Thickened intestines and enlarged lymph nodes. She was opened up and apparently intestines very inflamed, so much so they have difficulty closing the duodenum after biopsies. Histology report said IBD or possibly enteric lymphoma, so PARR test carried out. The conclusion was IBD, I did hear mention of enteritis but to be honest, I never did get a reason for it. Before I could get to her, she had licked some disgusting diarrhoea type poo over the field the afternoon before this started but the vet thought it too quick to be the cause of the problem.
The vet had said to keep her on the Purina HA until mid April, since when I have been adding boiled white fish, boiled chicken breast, tinned sardines and mackerel to the Purina HA - all in small quantities and that seemed ok, I have also tried some Butchers wet food (she used to have that in rotation with the Lukullus) and that was ok but I have added a bit of Country Hunter in the last couple of days and she has had mucus and diarrhoea again so back on just the Purina. I would say the scratching got worse on the Purina. Vet doesn't think she has a food allergy.
Sorry for the length of this but difficult to explain in fewer words.