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.
- 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.
- 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.