Ideas please .....

[Ttart]

My lovely 20 year old mare has been so easy to look after and has always looked superb and enjoys life & exersize - she's fed morning & evening and brought in most nights except in the summer when we leave her out a few nights - just before we left for our holidays in June we noticed she had a cough just 4 coughs then ok but we only went away for 7 days and despite being cared for by the best when we returned I was shocked at how much weight she had lost ☹️ 2 days later she had a huge back leg & the vet was called and she was treated for lymphangitis and the antibiotics she had were suitable for that & to treat a cough, she also had a Cushings test - results all clear, but things still werent great so another vets visit more antibiotics and I found signs of mud fever on her hind legs so we treated that, then I read about buttercups (her field has loads) and realised she has a lot of the systems they produce ... she has been moved to another field, wormed twice, eats like a pig, back to her sparky self but is still very underweight, shedding her summer coat and very scurfy plus a rumbling tummy (poos are perfect) anybody experienced anything similar - advice needed please

 

[Puddleduck]

It's possible to get a false negative result with a cushings test. Based on what you've described I'd suspect the she may have either had a false negative result or been just under the threshold at the time of testing.
This time of year is one of the seasonal peaks for cushings when many cushings horses show increased symptoms.
My old mare had the condition and in the early stages suffered with periodic lymphangitis in her hind legs and hoof abscesses.

 

[Pearlsasinger]

I have tl say I thought "Cushings" as I read your post. My Cushings are had skin problems and a horrible, long-drawn-out abscess until the Prascend kicked in. there is a different test which it would probably be worth doing.