Do you live with a Mr. Licks-A-Lot?
You know what I mean – a dog who, for reasons that he is not readily sharing, will suddenly and obsessively begin to lick the floor, the couch, the wall? Note that I am not referring to the dog who licks you, a behavior that usually communicates appeasement, affection, or in some cases, anxiety. Rather, the Mr. Licks-A-Lot that I am talking about is the dog who directs his obsessive licking primarily at inanimate objects.
Some dog folks, myself included, have associated a bout of this type of repetitious licking with stomach upset; and in the worse case scenario, as a reliable predictor of the impending vomit. An alternate explanation for excessive licking behavior in dogs is behavioral – specifically, that dogs who lick (a lot) may be experiencing anxiety, obsessive compulsive disorder, or age-related cognitive dysfunction. However, neither of these hypotheses had ever been studied scientifically. Until now.
The Study: A group of researchers at the University of Montreal Veterinary Teaching Hospital conducted a case-control study of dogs presenting to the hospital with excessive licking to surfaces (1). At the start of the study, owners completed a written history of the dog’s behavior, which included the type of licking, its duration, frequency and intensity, and the occurrence of any signs of gastrointestinal (GI) disturbance. They also were required to videotape one or more licking episodes. Nineteen “licks-a-lot” dogs and 10 non-licking control dogs were enrolled in the study. All 29 dogs underwent complete gastrointestinal, behavioral and neurological diagnostic evaluations. When a gastrointestinal diagnosis was found, treatment specific to the disorder was initiated. When no diagnosis was found, a placebo treatment was used. All dogs were reexamined 30, 60 and 90 days later.
Results:
- Licks-A-Lot Group: Of the 19 dogs who presented with excessive licking, 10 dogs (53 %) exhibited clinical signs of GI disturbance, and 14 of 19 (74 %) were diagnosed with a GI disorder. Problems included several types of inflammatory disease, delayed gastric (stomach) emptying, chronic pancreatitis, gastric foreign body, and giardia infection.
- Control Group: By comparison, 3 dogs in the control group (30 %) were diagnosed with a GI problem. The difference in GI diagnosis frequency between the Mr. Licks-A-Lot group and the control group was statistically significant (74 % vs. 30 %, P = 0.046).
- Resolution of Licking: Following treatment, a reduction in both the frequency and the duration of licking behavior was reported in 59 % of the affected dogs. Complete resolution of licking behavior was seen in 9 dogs (53 %). Note: The authors also reported that the study’s internist saw clinical improvement in 4 additional dogs when evaluated at 120 to 180 days.
- Behavior evaluations: Data collected through behavior profiles and video analysis found no differences in the degree of anxious behaviors shown by dogs in the licking group and dogs in the control group.
Take Away for Dog Folks: This study is the first to show that gastrointestinal disturbances may be the underlying cause of excessive licking of surfaces in dogs. Almost three-quarters of the dogs in this study were experiencing an undiagnosed GI disorder and more than half showed a complete cessation of licking behavior once the medical problem was resolved. The authors speculated that licking behavior may reflect feelings of nausea and/or abdominal discomfort in dogs. This new information does not eliminate the possibility that the underlying cause of excessive licking is behavioral in some cases. Rather, it suggests that the presence of an undiagnosed gastrointestinal disorder should be considered when a dog presents as a Mr. Licks-A-Lot and that we should avoid focusing on behavioral causes only when presented with this type of problem.
P.S. Fly biting and Sandifer Syndrome?
Pilot study: The same group of researchers published a case report that examined a possible connection between fly biting behavior in dogs and gastrointestinal disturbances (2). They studied 7 dogs who were presented for exhibiting snapping/jumping at imaginary flies using the protocol described above. All seven dogs showed sudden head-raising and neck extension movements immediately prior to jaw snapping and the behavior was most pronounced or only occurred immediately after eating. Like excessive licking, fly snapping behavior in dogs is often classified as having a behavioral rather than a medical cause. Most commonly, it has been classified as a form of epilepsy (especially in Cavalier King Charles Spaniels) or as obsessive compulsive disorder. In this study, all seven dogs were diagnosed with a gastrointestinal problem and were subsequently treated. When reevaluated 30 days following the start of treatment, fly-biting had completely resolved in four dogs and had partially resolved in one dog.
Possible cause? The authors compare the behavior of these dogs with Sandifer Syndrome, a problem seen in human infants that is believed to be caused by gastroesophageal reflux or delayed gastric emptying. It was postulated that the characteristic movements of raising the head, extending the neck, and in dogs, snapping/gulping air serves to reduce esophageal or gastric discomfort. Although preliminary, this case report suggests that just as with excessive licking behaviors, gastrointestinal disease should be considered as a potential cause of imaginary fly biting behavior.
References:
- Becuwe-Bonnet V, Belanger M-C, Frank D, Parent J, Helie P. Gastrointestinal disorders in dogs with excessive licking of surfaces. Journal of Veterinary Behavior 2012; 7:194-204.
- Frank D, Belanger MC, Becuwe-Bonnet V, Parent J. Prospective medical evaluation of 7 dogs presented with fly biting. Canadian Veterinary Journal 2012; 53:1279-1284.
The Science Dog 
Suggest that some licking may be to bring scent information to the vomernasal organ. Just a thought.
LikeLike
Wonderful article!
LikeLike
Thank you “Crawforddogs”!
LikeLike
Linda,
This is intriguing stuff because this symptom has vexed me my entire 30+ years as a veterinarian, but I have a few reservations. Do you feel the statistical power in this study is strong enough to confirm an association between excessive licking and GI disorder and disease? What are the time parameters for “excessive licking”? I am also concerned about complete resolution in only 53% when 74% were diagnosed with a GI disorder. This wide gap in association leaves room for some doubt about statistical verification. What are the time licking parameters for “clinical improvement” in the four additional dogs at 4-6 months post diagnosis?
You are a far more experienced statistician than myself so I am really interested in your response to my concerns.
Again, great post.
LikeLike
Hi Ken – Thanks for your comments. I agree completely that the statistical power of this study is low. One of the problems, as I know you are aware, with many dog health studies, especially clinical case studies, is low numbers (statistically speaking, the “problem of small numbers”). That said, the authors of the study were very careful in their interpretations of their results and also addressed a number of limitations with the study, including the difficulty of diagnosing inflammatory bowel disease and delayed gastric emptying (i.e. these are not simple yes/no diagnoses). There is also the possibility of a post-hoc error (and they did mention this also), meaning that some of the dogs would have stopped licking over time regardless of the intervention. Last, as you mentioned, not all of the dogs showed a response to treatment, suggesting that other factors are involved with excessive licking behavior in some dogs. The authors of the study did address this, as well. (I want to be careful to not misrepresent their paper, but also could not include all of the details in a blog essay). In my humble opinion, I think that given that this is a small study and that it is a case-control study, the information that we can take from its results is to consider gastrointestinal disorders as a possible underlying cause in some cases of excessive licking, but that it is probably a multi-factored syndrome rather than a single disorder. So looking carefully at gut health in these dogs should always be on the table as a differential. I think this may be especially important since many GI problems do take quite a bit of diagnostic testing to identify, and perhaps owners stop too soon in some cases by just assuming that it is a behavior issue. Finally, this provided at least a modicum of data suggesting that indeed, excessive licking (and perhaps fly biting!) may signify abdominal discomfort in dogs. Thanks again for your note – always great to hear from you!
LikeLike
I’m a dog trainer and a dog mom and this particular behavior has always stymied me. Having a bit of new knowledge will be most helpful when presented with this issue. Thank you for the post.
LikeLike
You are welcome – thanks for following! Linda
LikeLike
This is incredibly timely information. I was woken up at 4:30am this morning by Moses licking the carpet in our bedroom – something he’s never done before.
After ascertaining that he didn’t have a mouth injury, was able to eat and drink, and went outside with no issues, I brought him back in just in time for him to barf massively all over said carpet.
However, once out of his system, he really seemed to feel better and was happy to go outside and play, and didn’t resume licking the carpet. Put that as one check in the ‘stomach upset’ column, I think.
But all of this info is really great – definitely hadn’t even had the mind to look up this issue before this morning!
LikeLike
Well, there ya go. Glad that Moses is feeling better this morning and agree – that episode definitely lands squarely in the “GI Issue” column, I believe. 🙂
LikeLike
Pingback: Non stop chewing - My German Shepherd Forum
great article! Thanks
LikeLike
Sorry to be replying late 😦
But similar to this I have noticed that several of my dogs started eating ‘dirt’ when she became ill with ‘pancreatic insufficiency’. She tended to scrape the top layer of bare clayed soil — possibly for the algae that grow i such places. Since then I have found that ‘dirt eating’ tends to appear some time before a dog is noticeable ill.
I suspect that it is similar to humans and elephant who become dirt/clay eaters and is a response to some need in their system. Maybe the floor lickers are just dog who have not had the option of eating soils or grass because they are kept inside?
LikeLike
Pingback: Excessive licking of floor and walls | Theo Stewart – ‘The Dog Lady’
Interesting article. I hope someone will attempt to replicate the study.
There may be other sorts of licking.
One of my dogs reacted to the Sorresto flea and tick collar by compulsive licking of herself, particularly her paws. The person at Bayer who took my call (I’m pretty sure she was a veterinarian) said it was probably paresthesia, a pins-and-needles type reaction of the nervous system. When I took the collar off and washed her neckline thoroughly, the licking stopped.
LikeLike
My dog has been licking and gulping excessively and now an occasional head bobbing episode which my vet thinks is neurological and a seizure. Can the licking be associated with the neurlogical head nodding? My vet has treated him for acid reflux for over a year with no cessesation in the lick gulping area.The head nodding usually follows the lick and gulping event. Frustrating and exhausting.
LikeLike
I am not alone who has Mr. Licker. I wasn’t even aware that there already been several studies on this matter. Thanks for writing this wonderful article!
Nootan Kumar
LikeLike