DEAR DR. FOX: Thank you very much for your sensitive and helpful response to our July 2012 letter regarding Loki, our 13-year-old mixed-breed dog. We deeply appreciate your empathy for animals and those who care for them.

The following is an excerpt from our 2012 Christmas letter to our friends and family:

"Loki, poor Loki. In addition to having Cushing's syndrome and being blind, he was diagnosed this summer with vestibular disease -- that means he is dizzy (and he's not even a blond). He has, however, developed a certain sense of decorum.

"One night while being walked by Jon (dog-sitting while we were away), Loki picked up something from the street. Jon didn't notice it until walking up our driveway. He saw that it was a sandwich, probably discarded by construction workers next door. He tried to pry it out of Loki's mouth, but the dog would not give it up. Into the house Loki marched, went to his dog dish, deposited the sandwich and then ate it. I guess that legitimized the food. Not bad for a former street dog from Brooklyn."

Thank you again for being there for our pets. -- J. and M.H., Poughkeepsie, N.Y.

DEAR J. and M.H.: I have taken the liberty of sharing your intimate account of your beloved former street dog from Brooklyn.

In spite of his infirmities, he displayed better manners than many of our own species. Thanks to your devoted care of this old dog, he was not only able to enjoy some quality of life, but also to demonstrate a degree of sensibility that helps us deepen our appreciation for other creatures who enrich our lives in countless ways.

I like to think that we are beginning to settle the score of our indebtedness after centuries of exploitation and abuse of creatures -- wild and tame -- as more people support their local animal shelters, advocate animals' rights, oppose cruel factory farms and support wildlife and habitat protection and restoration at home and abroad.

Your story of Loki reminds me of a captive kit fox who deposited morsels of food around his cage mate who had died suddenly. As with humans, saving food can be a token of affection. For Loki, perhaps not gobbling the food he found in the street but bringing it home to eat in a civilized manner was a tribute to his preferred existence under your roof.

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 with euthanasia after finding metastatic disease.

By the time the symptoms appear, it is usually too late for treatment. My heart is breaking for this most recent loss.

Is there any clinical way to prevent this? -- K.W., Tacoma Park, Md.

DEAR K.W.: My sympathies go out to you and all those people in your situation, where cancer is discovered in a beloved animal and it has spread so much that nothing can be done.

Part of the problem is that it is not always easy to know when an animal is in pain or not felling well. Whenever in doubt, go to the veterinarian. Also go to the veterinarian every six to nine months for a checkup when you have an animal in the "old age" category, and annually up to the end of middle age, which can be around 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.

(Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Universal Uclick, 1130 Walnut St., Kansas City, MO 64106. The volume of mail received prohibits personal replies, but questions and comments of general interest will be discussed in future columns.

Visit Dr. Fox's website at DrFoxVet.com.)

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, Md.

DEAR M.C.M.: I appreciate your writing to me about this article on a finding that has been widely publicized.

This is an important issue because while 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 whom continue to suffer a variety of health problems because their diets contain more starches than an obligate carnivore like a cat can handle. Dogs are more omnivorous than cats, just as foxes and coyotes are more omnivorous than wolves and cougars.

For a more detailed response, see my article "Domestication and Diet: Dog Genes and Cat Gut Bacteria," posted on my website, DrFoxVet.com.

DEAR DR. FOX: I have two Shetland sheepdogs. Both are 7 years old, but they are not related.

When we were in Florida last March, 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 like he lost some hair on his face since you could see the pink skin beneath.

I took him to the vet, and he said that there are a lot of molds and spores on the ground in Florida. He put my dog on prednisone, as he said the rash was inflamed. This did calm down the redness. However, 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 due to the fact that 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. However, we don't want to put our dog through that unless it's absolutely necessary.

I have done some research online and found that there is such a thing as 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?

Years ago when I bought my first dog, I read your book "Understanding Your Dog." This was one of the most insightful books I've read on dog behavior. -- G.J.D., Naples, Fla.

DEAR G.J.D.: I am impressed by the number of readers who are going online in search of diagnoses for their pets' conditions when prescribed treatments fail or when veterinarians fail to communicate clearly or offer opinions that don't seem to make sense.

I find it disturbing that a veterinary dermatology specialist -- and I would ask if she is board certified -- 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 -- these should also be considered.

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.

MORE PET FOODS AND TREATS RECALLED

Steve's Real Food announced a voluntary recall of its 5-pound bags of Turducken Patties due to potential contamination of salmonella. Consumers with questions should call 888-526-1900 or email help@stevesrealfood.com

Diggin' Your Dog announced that they are voluntarily withdrawing one lot of its Strippin' Chicks Pet Treats due to a potential contamination of salmonella. Consumers with questions should call 775-742-7295 or email info@dydusa.com.

Diamond Pet Foods is issuing a voluntary recall to Premium Edge, Diamond Naturals and 4health Dry Cat Food Formulas due to the possibility of low levels of thiamine (vitamin B1). Consumers with questions should call 888-965-6131 or visit petfoodinformationcenter.com

(Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Universal Uclick, 1130 Walnut St., Kansas City, MO 64106. The volume of mail received prohibits personal replies, but questions and comments of general interest will be discussed in future columns.

Visit Dr. Fox's website at DrFoxVet.com.)

DEAR DR. FOX: I adopted two sweet sister cats nine years ago -- Chase and Chochi. They've not had any major health issues until recently. They are indoor cats, although they are allowed to go out on our deck with us.

More than a year ago, I noticed Chase had lost some fur on her lower abdomen. Shortly after, we embarked on a home renovation that was loud, dusty and forced us to leave our Maryland home for several months and move into a vacation home in West Virginia. In West Virginia, I found a vet who said Chase was overgrooming due to a flea saliva allergy. She recommended Comfortis. She also noticed Chochi was overgrooming the same area, so both cats began the drug. Neither cat improved, so we went back to the vet, who found Chase, in particular, had redness and a possible staph overgrowth. Blood work on Chase was normal. Both cats received antibiotic injections, two doses one week apart. Chochi improved, but Chase began removing more fur. She received a shot of steroids and two laser treatments. The vet also recommended resuming the Comfortis, and the redness went away.

We moved back to Maryland, and Chase continued to overgroom. She now has bare-looking thighs, abdomen and upper chest. I took her to a vet two weeks ago, and this vet observed that Chase had no noticeable irritation and diagnosed her as having "psychogenic alopecia." She recommended continuing the flea treatment and starting with a homeopathic remedy. It seems to have had no effect. The next recommendation was Prozac.

Help! Since the cats are essentially indoor cats, I have wondered about the accuracy of the flea allergy diagnosis and treatment. I have never seen a flea, although at the start of the treatment ordeal, the vet did observe some possible flea casings in Chase's fur. The deck in West Virginia occasionally gets mouse and squirrel visits; the Maryland deck has only birds.

Both cats threw up shortly after the Comfortis after the last two injections. In looking at other options, I was recommended Frontline or Revolution. Both vets felt the symptoms were inconsistent with ringworm. -- P.H., Silver Spring, Md.

DEAR P.H.: Fleas leave telltale feces, not "casings" in animals' fur. Since you make no mention of your cats being tested for hyperthyroidism -- meaning it was not considered by the veterinarians -- I would seek a third opinion.

Considering your cats' ages and symptoms, hyperthyroidism is the first possible cause to consider and rule out before considering a specific allergy. Excessive grooming in our formally feral cat was quickly resolved when salmon was removed from his diet.

Let me know if thyroid disease is the problem, and inform the veterinarians, who should have considered this possibility from the start.

DEAR DR. FOX: One of my dogs had chronically loose stools. I have made one simple change that has completely resolved the issue.

We adopted the dog as a 1-year-old and have had him for three years. He is a labradoodle and is lean and otherwise healthy. I feed all three of my dogs a mixture of wet and dry Wellness food and some fish oil. For the labradoodle, I tried all sorts of added ingredients, including sweet potato, psyllium flakes and yogurt. Each one helped at first, but the benefit did not last. The owner of his littermate said his dog had the same issue, so I thought it must be part of this particular breeding line.

My dogs had free access to a large backyard where they could romp around at will, though most of the activity involved charging out to bark at a squirrel or a neighboring dog. They also got 30 minutes off-leash every day at a dog park. I thought things were going well.

We recently moved to a house in the hills with no yard at all. This requires me to give the dogs regular scheduled walks on a variety of routes around the neighborhood. It's not even for very long, sometimes just a brisk 20 minutes twice a day if that's all I can fit in. And every few days we have a two-hour off-leash hike where they can go full speed up and down the trails. That is the only change. With this routine, the labradoodle's stools are now healthy, and the other male dog has stopped marking inside -- though that may be due to less stimulation from other dogs walking past the house.

I just want to reinforce to your readers the importance of brisk and perhaps routinely scheduled walks. -- G.W., Topanga, Calif.

DEAR G.W.: Brisk, routinely scheduled walks and off-leash romps in safe and dog-sanctioned open space are all part of holistic canine health care. Experienced veterinarians always determine such lifestyle factors in making a diagnosis and in recommending appropriate treatment for a variety of health problems.

A strict activity routine before meals helps prime the dog's appetite and digestive system before coming home and anticipating food. This mimics the dog's natural hunting/gathering/scavenging behavior -- physical activity to various degrees of strenuousness before eating two or three small meals daily. One big meal can mean bloating, vomiting, indigestion and loose stools.

(Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Universal Uclick, 1130 Walnut St., Kansas City, MO 64106. The volume of mail received prohibits personal replies, but questions and comments of general interest will be discussed in future columns.

Visit Dr. Fox's website at DrFoxVet.com.)