Most ill dogs could receive a pet multivitamin supplement safely and possibly with benefit to overall well-being. Vitamin C is often prescribed to be administered with ketoconazole. This aids absorption of the drug by helping to acidify the stomach and may also "boost" the dog's immune system. Use of the vitamin C should be checked with your veterinarian as high doses may cause gastrointestinal irritation.
Talk to your veterinarian about your dog's overall nutrition status and the nutritional goals you need to meet while your pet is ill. The more ill your dog, the more important it is to discuss this issue with your vet. Your veterinarian may have special recommendations, such as hand feeding or appetite stimulants, for dogs that are eating poorly or not at all with Valley Fever. In rare cases, placement of a feeding tube should be considered to meet the nutritional needs of patients that will eat nothing or nearly nothing.
Alternative therapies, such as herbs or acupuncture, have not been scientifically tested to treat Valley Fever. The majority of veterinarians to whom I have spoken use these therapies adjunctively with antifungal drugs to help support the dog's overall health and to improve function of the immune system. If you wish to pursue alternative treatments, this author recommends you consult a veterinarian trained in holistic medicine. These professionals are your best source of help.