cocker spaniel w/ eating issues

Question
I have been reading your posts about my cocker spaniel's skin issues.  She's been very itchy.  Our vet chalked it up to food allergies; we have recently changed back to her old food (Purina One).  Her itching is clearing up, but she hasn't been eating hardly at all.  Our vet said she wouldn't starve herself, but it seems that's exactly what she's doing.  She's been vomiting bile.  I imagine the bile is from the lack of food, but what is making her vomit in the first place?  We noticed today she seems to be thinner than normal.  I'm worried about the vomiting considering she isn't eating nearly enough to be throwing up.  What do you think this could be?

Answer
Purina is one of the worst foods on the planet.

If she's not eating...and vomiting bile...get her back to the vet asap.

Try feeding her small amounts of plain boiled chicken to see if that will stay down. (no bones - no skin).  A bit every few hours.

And, by the way, itching is caused by food allergies only about 5% of the time.

I can't advise further on the skin issues because I don't have enough information or know what you've tried.
Delores