Dear Dr. Fox:

A recent front-page article in The Washington Post, “Wolf-to-dog evolution went with the grain,” states, “In particular, dogs show changes in genes governing three key steps in the digestion of starch . . . it makes us convinced that being able to digest starch efficiently was crucial to dogs.”

The article suggests that once dogs began living close to humans, they found a new feeding niche by scavenging human garbage. The implication is that grains are not harmful to dogs because their digestive systems have adapted to diets other than meat. In light of this, have you changed your recommendations about feeding dogs mostly grain-free foods?

M.C.M., Silver Spring

DF: This is an important issue because although dogs — some breeds better than others — have evolved the enzymes needed to process carbohydrates and starches from grains and potatoes, this adaptation does not mean that a high or even moderate carbohydrate content in dogs’ diets is optimal for their health.

For most dogs, I advocate low levels of grain, but not for cats. A minute amount as a binder for dry foods is acceptable for cats, many of which continue to suffer a variety of health problems because their diets contain more starches than an obligate carnivore such as a cat can handle. Dogs are more omnivorous than cats.

For a more detailed response, see my article “Domestication and Diet: Dog Genes and Cat Gut Bacteria,” on my Web site,

frequent checkups

Dear Dr. Fox:

I just lost my third dog to cancer. They were all about 10 years old. They all had a sudden onset of acute symptoms, followed closely by euthanasia after finding metastatic disease.

By the time the symptoms appear, it is usually too late for treatment. Is there any clinical way to prevent this?

K.W., Takoma Park

DF: Part of the problem is that it is not always easy to know when an animal is in pain or not feeling well. Whenever in doubt, go to the veterinarian.

Also go to a veterinarian every six to nine months for a checkup for animals in the “old age” category, and annually up to the end of middle age, which can be about 6 or 7 for some breeds and 9 or 10 for others.

Going in on this schedule, and not just when the animal needs shots or seems ill, can lead to early detection of cancer, which means that effective treatment would be better assured.

online help

Dear Dr. Fox:

I have two Shetland sheepdogs. Both are 7 but not related.

When we were in Florida last year, one of my dogs developed a rash under his nose. It was red, and he was rubbing his face on furniture and licking his feet. It looked as though he lost some hair on his face since you could see the pink skin beneath.

The vet said there are a lot of molds and spores on the ground in Florida. He put my dog on prednisone, because the rash was inflamed. This did calm down the redness. When we returned to Michigan, my vet there also put him on prednisone, but after repeated use, the area looks pretty much the same.

I noticed that the dog was beginning to get a white patch on his face that hadn’t been there before. It’s gotten larger, and other patches are beginning to appear.

I have taken him to a vet who specializes in dermatology problems in dogs. She said that it was just his hair. I don’t think that’s the case because he is getting more white patches. She did a blood test that indicated he was allergic to dust mites. She also suggested that a punch test would show more. We don’t want to put our dog through that unless it’s absolutely necessary.

I did research online and learned about vitiligo, a condition that causes depigmentation of skin in dogs. The pictures looked similar to what is happening on my dog’s face.

What would you suggest at this point? If it is vitiligo, is there anything that can be done?

.J.D., Naples, Fla.

DF: I find it disturbing that a veterinary dermatology specialist did not raise the possibility of your dog having discoid lupus erythematosus, a chronic skin condition with inflammation and scarring of the face, ears and scalp, which is common in your breed.

This condition fits the symptoms you describe. Other autoimmune disorders to which Shetland sheepdogs are susceptible include pemphigus foliaceus and pemphigus erythematosus.

Carefully monitored, long-term treatment with prednisone can help, especially in combination with tetracycline, niacinamide or gold therapy (aurothioglucose), fish oil and topical vitamin E.

Michael W. Fox, author of a newsletter and books on animal care, welfare and rights, is a veterinarian with doctoral degrees in medicine and animal behavior. Write to him at United Feature Syndicate, 1130 Walnut St., Kansas City, Mo. 64106.

2013 United Feature Syndicate