Saturday, December 7, 2013

Vanishing Winnie. Vitiligo in A Chocolate Lab.


Winnie's first vet visit at 8 weeks old.
I met Winnie when she came in to the clinic for vomiting and diarrhea after eating a rug 3 days before. (BAD! BAD Winnie!). On presentation she looked very normal. Her physical exam also revealed no abnormalities in the gi tract, but her face!. Well, her face was not only a terrific blog topic, but it was something her dad and I talked about for almost a half an hour.

Winnie is a 2 yr ear old chocolate lab who started out looking like every other chocolate lab. Brown from stem to stern..no spots, no color changes, no interruptions. She was one solid Hershey's brush stroke from nose to the tip of her tail. Until one day about a year ago when a little pink spot on the left side of her brown nose appeared. For those of us aging women her liver spot was a bleached blemish. Her dad brought her in to see if there "might be some kind of skin disease occurring?"

For those of us veterinarians who are not boarded dermatologists the barely visible, not quite taking a stand, not really bothering the pet, not sure if normal or abnormal lesions? are the ones we sit hand on hip, finger on temple wondering with a puzzling pursed look pining over. I promise, these are the lesions I lose sleep over. I call them the "toss of the coin" lesions. (As a matter of personal pride I do not toss the coin in front of my clients..but I do sometimes admit to wanting to).


Such was the case with Winnie on her visit a year ago. That little pink smudge on the left half of her nose was odd. It wasn't raised, irregular, or bothering her. It sort of just looked like a pink paint smudge. BUT, there are diseases that can cause the skin to change. And some of these are really, really, bad diseases, like cancer, or immune mediated diseases. The immune mediated diseases have to be beaten into submission with high doses of steroids, that if needed long enough will kill you! Oh, gosh, we hate to talk to parents of a one year old about cancer, or disfiguring, life stealing diseases. No one wants to be an alarmist, but we also don't want to ignore something that we might be able to treat to cure now, versus wait and try to treat (possibly too late to do so) later. Oh, the nail biting!


And there sat Winnie at her exam a year ago. Smiling, wagging, and splotched. She thought that she was just fine. So, why would we argue with her. Your patient always tells you the most important pieces of your diagnosis. If your patient is down and out depressed, and not looking like they want to put any effort forth to struggle with your poking and prodding then something is WRONG! Listen to them. But, if like Winnie they are thinking everything is just honkey-dory then listen. A casual neglectful approach is sometimes the right decision. For Winnie it was the correct diagnosis.


Vitiligo is a disorder that causes a lack of pigment due to the disappearance of the epidermal and/or follicular melanocytes. No one really knows why. It could be immune mediated, it could be triggered by some unknown cause, it has a genetic link, but no identifiable etiology. It sort of slowly creeps up, and then creeps along the skin erasing the color that used to be there. It affects about 1-4% of humans thereby making it an important area of study for dermatologists. Loss of pigment leaves skin more susceptible to sun damage which can increase the chance of skin cancer. 

In dogs it is usually seen around the face, but can affect the whole body. It is characterized by loss of pigment in the skin causing the resulting hair in that area to grow out white. Some dogs lose the hair and when regrown it is white. There are no corresponding skin lesions. Dogs with skin infections, or trauma to the skin can lose hair and it may grow back a different color, or not at all. But these dogs tend to lick, itch, traumatize the skin, or have crusting, flaking skin, or pustules that resemble pimples or fluid filled bumps. These dogs should be seen by a veterinarian and have a work up to identify the source of the skin problem and receive an appropriate treatment plan to address the underlying cause and any subsequent secondary skin infection, etc. Diagnostics for skin lesions can include blood work, skin scrapes, cytology, impression smears, cultures, and biopsy. If there is no lesion with loss of pigment of the skin, resultant white hair (medical term is leukotrichia),  then the diagnosis is vitiligo. 


There is no treatment for vitiligo. This is a cosmetic condition and will not affect Winnie in any way. She does need to be careful not to burn her skin, especially the non-haired areas like her nose and eyelids. There is a much higher incidence of skin cancer in white dogs and cats. On cats we see it most often on the nose and ear tips (non-haired and point to the sun).


Winnie at 2-1/2 yrs old.
Her dad continues to watch her for any changes in her skin, the hair, and at every yearly exam we will photograph her for any changes or advancement of her vitiligo. 

Oh, and as an foot note, for those of you that are worried, Winnie recovered without any further incident from the rug eating fiasco.

If you have a pet related question you can find me at Pawbly, or on Twitter @FreePetAdvice. I would be happy to help you in any way that I can.

3 comments:

  1. How common in this? I'm a vet student at the moment, but I worked in a clinic for a couple years before school and I have never seen it before. It's pretty cool!

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    1. Hello Michelle,
      I have only seen it (well, that I recognized) once in 8 years. So probably not common. I did some research of VIN, there were lots and lots of people asking if the dog they were seeing had this condition. It seems rare enough that all of us vets feel compelled to ask an expert for a confirmation.

      Best of luck in school.

      Sincerely,
      Krista

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  2. She was one solid Hershey's brush stroke from nose to the tip of her tail. Until one day about a year ago when a little pink spot on the left side of her brown nose appeared. For those of us aging women her liver spot was a bleached blemish. Her dad brought her in to see if there "might be some kind of skin disease occurring?" the natural vitiligo treatment system

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