I only just realized where you live, has he been tested for Valley Fever?
Here are some of the symptoms of disseminated Valley Fever:
? lameness or swelling of limbs
? back or neck pain
? seizures and other manifestations of central nervous system swelling
? soft swellings under the skin that resemble abscesses
? swollen lymph nodes under the chin, in front of the shoulder blades, or behind
the stifles
? non-healing skin ulcerations or draining tracts that ooze fluid
? eye inflammation with pain or cloudiness
Here is a link to a full article on Valley Fever, http://www.vfce.arizona.edu/Content/Documents/Valley%20Fever%20in%20Dogs%20for%20PDF.pdf
I know there is at least one person on the forums that had a dog with disseminated Valley Fever.
