Mucormycosis in Dogs

Mucormycosis is a general term for certain fungal infections affecting various species, including canines, equines and humans. If your dog is diagnosed with zygomycosis, he's suffering from a mucormycosis infection. These common fungi usually don't bother people or animals with a normal immune system, but those with a compromised immune system might be at risk. Mucormycosis usually affects a dog's sinus and nasal passages, or his skin.

Mucormycosis fungal infections consist of pathogens falling into the order Mucorales, including the class of zygomycetes causing zygomycosis. Depending on the fungi involved, the disease might progress rapidly -- especially in dogs with immune systems issues -- or result in chronic infections. The latter occur more often in relatively healthy canines. Basidiobolomycosis and conidiobolomycosis are the most common of these zygomycotic infections in animals.

Nasal infection symptoms include a pus-filled discharge, frequent nose pawing, sneezing and nosebleeds. Because the disease is so rare, it's likely that a dog with these symptoms is not suffering from mucormycosis. However, if your dog receives treatment for a chronic nasal discharge and there's no improvement over time, there's a possibility he has a mucormycosis infection. Your vet can collect samples of your dog's nasal discharge and send them to a laboratory for specific testing.

If your dog is diagnosed with a mucormycosis nasal infection, your veterinarian likely will prescribe long-term treatment with itraconazole, marketed under the brand name Sporonox. This antifungal medication generally has few side effects, although it can cause liver disease. More common side effects include vomiting and diarrhea and appetite loss. Expect your dog to require itraconazole therapy for many months, or for the rest of his life. Dogs taken off the medication after their condition improves might suffer a recurrence.

The skin infection results in itchy, draining, ulcerated lesions, usually found on the dog's legs or body. Since the skin infection is uncommon, it's also a case of additional investigation on the part of a veterinarian after conventional treatment fails. The pathogen, seldom affecting dogs, must be isolated in the laboratory for diagnosis. Surgical resection of the affected tissues, accompanied by itraconazole therapy for several months, is the recommended therapy. The third edition of "Infectious Diseases of the Dog and Cat" notes that such treatment is not "straightforward," as the therapy has been described in just a few patients.