well vets do not have much training in the area of diet and nutrition so that may be one reason, and also, if you are buying the food at your vet, changing food will take money out of the vet's pocket.
You need to do what is best for your dog. You've started to educate yourself - that is so important. Try some new foods and find one he likes. You can even write a lot of the companies and they will send you samples. There is a sticky thread at the top of this Health & Diet forum with all the email addresses - I wrote them and told them about my dogs and my cat and they were all very generous in their samples. That way you can find what your boy likes best. Although if he has been eating Eukaenba he will probably think everything tastes better -- dogs do know quality.
Good luck getting the skin cleared up. I would also stay on top of keeping his bedding clean.
We had problems with skin too this year and my holistic vet gave us this shampoo - it is wonderful Photoclens by Ayuvet from Tomer Labs - you can buy it directly from them
natural herbal treatment - tomer laboratories - natural quality herbal remedies -- this shampoo is wonderful - the dogs smell wonderful & their coats are beautifu.
Here is what I found about the ingredients
oils of Himalayan cedarwood
Cedarwood Himalayan Essential Oil, Cedarus Deodora
Eucalyptus leaf oil
Eucalyptus Essential Oil, Eucalyptus globulus
Also, Eucalyptus is suppose to deter fleas
