Dear Doctor

Letters to Tufts Veterinarians - August 2014


The dog is afraid of strangers

Q I adopted a mixed breed dog when she was eight weeks old — she seems to be part King Charles cavalier spaniel and part something else — and she’s an absolute doll, as long as she’s in the house with us. Ivy loves to play and sit on our laps, learned the ropes of relieving herself by the time she was three months old, and is generally a joy. But she is scared to death of people approaching her to pet her — not friends we have over to the house, but on the street when I’m walking her, which happens a lot because she is so adorable. I keep telling her soothingly that it’s okay, no one is going to hurt her, but the problem only seems to have gotten worse. What can I do?

Brenda Igoe

Traverse City, Michigan

Dear Ms. Igoe,

AStop letting people come up to her and pet her. A lot of dog owners believe the right way to desensitize their dog to something she’s afraid of is to throw her into the deep end of the pool, so to speak. That is, they keep putting her into the very situation that terrorizes her in the belief that repeated exposure will take the edge off.

We understand the impulse. Many people, in fact, feel embarrassed by their dog’s behavior, which is why they might put her in situations that terrorize her. They feel they must say “yes” if someone asks, “May I pet your dog?”

The problem is, that approach won’t work. It’s called flooding, and it only makes things worse. The person means well, but the dog finds the introduction horribly intrusive and scary.

So how do you desensitize a fearful dog? Very very gradually.

Start by taking charge of the situation in order to protect your young pet. When someone asks to pet her, respond, “Please don’t. I’m training her to stay calm around people, and that’ll make her nervous. She’s not there yet.” That will keep strangers out of her personal space.

What you can do is stage encounters with people the dog has never met whom you know to be gentle and soft spoken and who are willing to play the role of accidental pedestrians. Before you near each other from opposite directions at the appointed time, the person should be informed not to stare at your puppy or even pay her any attention, which she would perceive as aggressive. Also, your friend should not walk straight at you and your pup. Ask him or her to come toward you a bit circuitously. Ivy will perceive that as less threatening.

After acting out this scenario a few times, on a few different streets with a few different people, if you see that your dog has calmed down a little, stop to chat with a person you’ve engaged to act in your desensitization program. Your friend should still not look at your dog or try to interact with her, but he or she can nonchalantly throw a piece of an amazingly delicious food like freeze-dried liver at her feet while chatting.

Over time, your pup will come to realize that just like in the house, you are making sure for her that bad things will not happen. Indeed, she will see that humans, even those who have not been admitted into your “den,” can be tolerated and even enjoyed for the gifts they might bestow.

The tumor is a grade 2

QMy dog has been diagnosed with mast cell cancer, and the vet says it’s a grade 2. What does that mean? Is he going to live?

Art Ramus

Riverside, California

Dear Mr. Ramus,

Mast cell cancers are one of the most common malignancies of dogs. Mast cells are immune cells found throughout a dog’s body, so they can occur in virtually any tissue. But they most commonly originate in the skin or the subcutaneous fat just under the skin, appearing as lumps or bumps. Among the breeds reported to have a higher incidence: boxers, Boston terriers, Labrador retrievers, beagles, schnauzers, and Shar-Peis. But no breed is immune.

To diagnose the cancer, a dog’s veterinarian first performs a needle aspirate to ascertain whether the tumor is in fact a mast cell tumor. Even normal tissue has the occasional mast cell, since mast cells are everywhere in the body. But if it’s cancer, a stained slide will show far more mast cells than are present in normal tissue. We assume your dog’s doctor took that step.

After the needle aspiration, a veterinarian may order a chest x-ray to determine whether the malignancy has spread to the lungs. She’ll also palpate (feel) and perhaps aspirate the lymph nodes in the region of the tumor to check to see if the cancer has spread, or metastasized. At that point — after either removing the tumor or biopsying it — she’ll send a tumor sample to a pathologist. It’s the pathologist who grades the tumor based on the cancerous cells’ characteristics, which he can determine under a microscope.

A grade 2 tumor means the glass is more than half full. Of course, grade 1 is the least serious. Rather than spreading, it remains a local phenomenon, invading only the surrounding tissue. It’s easy to cure and doesn’t interfere with the dog’s life-

span. A grade 3, on the other hand, comes with a poor prognosis. It almost invariably metastasizes and tends to be associated with a survival time of only a few months, regardless of whether or not it’s treated. One of the reasons is that grade 3s tend to degranulate — particularly when they’re operated on — meaning cells in the tumor break open and release histamine and other substances that can cause gastric ulceration even if the tumor is not near the abdomen. Degranulation can cause other problems as well. (In cases in which surgery is performed on grade 3 tumors, antihistamines are often given prior to surgery to help prevent complications.)

A grade 2 cancer metastasizes about 20 percent of the time — one in five cases. Like a grade 1 tumor, a surgeon removes it with wide margins of normal tissue around it, since mast cell tumors are notorious for their ability to deeply invade nearby tissue. Whereas most tumors call for a one-centimeter margin around the cancer, the surgeon will try to get a two-centimeter margin — almost a full inch. If a two-centimeter margin is not doable, say, because the tumor is in a spot with very little adjacent tissue to close the wound, such as on a paw, radiation therapy might be recommended to target whatever part of the tumor might not have been excised. Fortunately, mast cell tumors are very responsive to radiation therapy.

The bottom line: while we can’t say with certainty that all will go well for your dog, the odds are on his side.

Infected withtick-borne Ehrlichia

QMy three-year-old coon hound mix must have been bitten by a tick before we rescued him at the age of one year. He has been diagnosed with ehrlichiosis and treated with doxycycline for 8 weeks. But he still tests positive, although he is currently sub-clinical, with no symptoms. Is there any other treatment to get rid of the Ehrlichia from his blood, when the doxycycline doesn’t work?

Honora Rappaport

Bloomfield Hills, Michigan

Dear Ms. Rappaport,

AWe assume you regularly apply tick medicine to your dog, which is why it appears he was bitten by a tick before he came to live with you. You are doing the right thing. Through another tick bite, a pet can become reinfected with Ehrlichia, which are somewhere between bacteria and viruses and can take up residence in white blood cells. By applying tick medicine on a regular schedule, you are making sure that you do not put him in double jeopardy, so to speak.

Tufts veterinarian Michael Stone, DVM, explains that there are many types of Ehrlichia (including Ehrlichia canis, E. chaffeensis, E. ewingii) that can infect dogs, each with specific signs and treatment plans. The infections typically cause signs of illness demonstrated by loss of appetite, listlessness, fever, swollen lymph nodes, and in some cases, lameness.

The most commonly used tests for Ehrlichial infections in dogs detect the presence of antibodies in the blood, Dr. Stone points out. After successful treatment, antibodies will persist in the blood for a variable period of time. So we are not overly alarmed by the fact that your dog still tests positive after treatment; it may simply mean that antibodies have persisted in the blood but that the actual offending organisms are gone and your dog has recovered completely.

That said, Dr. Stone points out that the most serious Ehrlichia, E. canis, can cause persistent infection that results in permanent tissue damage or even death, with the possibility of symptoms remaining dormant (sub-clinical) for some time and then returning (chronic). Thus, the exact course of treatment and significance of the test results should be discussed with your veterinarian. For instance, some dogs end up needing blood transfusions or intravenous fluids.

Because ehrlichiosis is not common in Michigan (and most cases of the dangerous E. canis occur in the southwest and the Gulf Coast), your doctor may wish to consult with a board-certified internal medicine veterinarian to discuss the significance of the positive test result. You absolutely should not panic. Just leave no stone unturned in case there is more to be done to rid your dog of the pathogens.


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