Obsessive Licking, Hot Spots and Cancer: Is There a Connection?

While the Red Dog Blog began as a way to keep friends and family apprised of our dog's progress in her courageous battle with cancer, it has evolved into a small but vibrant community where we can share a mixture of fun and facts with the dog lovers in our lives. Through our experiences with cancer, we have learned much - both about ourselves and the disease itself - and we want to share some of this with those of you who are interested.

(We also plan to implement some of the suggestions shared in response to our recent "Curious" post. Special thanks to both Amy & LiveWorkDream for the awesome feedback!)

Today, we'll talk about what we consider to be a potential "canary in the coal mine" indicator for the disease itself. Although little has been said about obsessive licking and hot spots being possible warning signs that your dog might have cancer, much discussion has centered on the facts that these behaviors can indicate anxiety, discomfort and pain. In our experience, all may have validity.

One potential mitigating factor is that Golden Retrievers can lick obsessively as a breed characteristic; what we are discussing, however, is not so easily explained. That the behavior can be expressed in any breed or mix gives credence to the belief that the behavior is not idiopathic, but rather has causation. In addition, veterinary scientists have documented many instances where underlying conditions were present prior to the behavior. This also suggests causation.

In our cases, all instances involved Shiva (Golden Retriever), Katy (Golden Retriever) or Snoopy (Basset/ACD mix). All have obsessively licked, thereby creating "hot spots" on multiple occasions for both physiological and psychological reasons, although both Retrievers also have obsessively licked surfaces such as furniture fabric and carpet. Ideally, both causes could be identified, although explaining the motivations and psyche of a dog tends to stray into the realm of speculation. In these instances, all we can do is hypothesize the most probable cause or causes of the behavior.

For that reason, as well as our hypothesis that cancer may be one potential underlying cause of the behavior, we will focus on instances having likely physiological causes. Although Shiva initially presented the behavior sporadically at a fairly young age (which we attributed to psychological motives), it was not until a recent instance that a definitive physiological condition could be linked to it.

Prior to receiving her diagnosis of osteosarcoma in 2009 - and prior to any limping behavior - Shiva began obsessively licking the anterior (front) side of her lower rear leg (metatarsus segment). Over the course of a week or two, she developed a classic hot spot. Unsure of her motivation, we sprayed an anti-itch agent on the area to discourage her from continuing.

Given her history with psychological stressors, we knew it could get much worse without intervention. In this case, she refrained for a short while, turned her attention to licking her dog bed and then resumed licking her leg with diminished regard for the distasteful agent. Within another week, she began very subtle, intermittent limping while continuing to obsessively lick her rear leg. This behavior increased in frequency and severity with some rapidity, which triggered a trip to the veterinarian.

The rest of the journey of surgery and recovery can be viewed here. After the removal of her right front leg and its subsequent healing, the licking behavior vanished. Please note that the limb affected by cancer and the one she licked were not the same.

As many of you know, a few weeks ago I discovered a mass between the toes of her remaining front leg. What you don't know, however, is that a couple weeks prior to this discovery she began obsessively licking the same spot on her rear leg as in the previous instance. She also licked the fabric on our couch into a soggy mess on multiple occasions. Since the removal of the new mass (which also proved to be cancer - melanoma this time), the behavior once more stopped. Again, the affected limb and the limb she licked were not the same.

In both instances, the intensity of the licking behavior and subsequent hot spots were indicators of something being amiss elsewhere in her body. For this very important reason, we suggest casting a wide net when searching for possible causes if your dog presents and persists with this behavior. While the cause may be in the limb being licked (cuts, sprains, foreign objects in paw etc.), in our experience it just as likely is not.

In Katy's case, her licking behavior has been less consistent, as well as more focused on fabric surfaces. The one exception is immediately prior to her recent diagnosis of hemangiosarcoma. In hindsight, there was a marked increase of obsessive licking and general unease which likely indicated her internal discomfort. Since the removal of her spleen, very little licking behavior has been evident.

With Snoopy, we were fortunate that neither instance pointed to cancer. The first example of obsessive licking indicated a soft tissue sprain in a rear leg. Unlike Shiva, he focused his attention on the pads of a front foot. After treatment, the behavior stopped. The second episode actually involved the same foot being licked, but the source of discomfort was a different spot than he was licking. Upon closer inspection, we discovered he had split his dewclaw down to the quick and was suffering acute pain from the injury. Sedation and careful trimming by our vet - followed by pain meds - solved that dilemma, as well as his licking behavior.

The bottom line for us is to never forget to take a whole-body approach when investigating persistent symptoms in your dog. Things are not always as they appear.

Our hope here is to foster discussion - and ultimately research - on this subject, so that those of us unfortunate enough to face cancer in our beloved dogs can have every opportunity of successfully fighting it. In most cases, the window for effective intervention is small, so time is of the essence. Perhaps obsessive licking behavior is one more diagnostic advantage we can use to tip the balance in favor of our canine friends.

Please share this entry with dog lovers everywhere, and add your own experiences and opinions to the comments below.