A POSSIBLE GI TIE
Two studies by a group of researchers at the University of Montréal Veterinary Teaching Hospital have investigated medical
causes for excessive licking of surfaces and fly biting in dogs.3,4 This research suggests that at least some of these cases are related to medical issues causing nausea or discomfort, thus
triggering the odd oral behaviors.
Excessive licking study
In a prospective clinical study by this group of researchers, 19 dogs that displayed excessive licking of surfaces were compared
with a control group of 10 healthy dogs.3
Complete medical and behavioral histories were collected for all dogs, and they all underwent physical and neurologic examinations.
Each dog then underwent a thorough diagnostic evaluation that included an abdominal ultrasonographic examination, an endoscopic
examination, and biopsies of the stomach and proximal duodenum.
For those dogs that licked, the mean duration of the licking behavior was 32 months, and 16 of the 19 dogs licked daily. The
medical evaluation revealed that 14 of the 19 licking dogs had GI abnormalities, which included lymphocytic-plasmacytic infiltration,
chronic pancreatitis, and, in one dog, a gastric foreign body.
Treatment of only the underlying GI disorder resulted in significant improvement in a majority of dogs in the licking group.
While no GI disorder was identified in five of the 19 dogs in the licking group, four of these five improved with use of a
hypoallergenic diet plus antacid or antiemetic medication.
Fly biting study
The same group of researchers also published a prospective case series that evaluated seven dogs that were presented with
a history of daily fly biting behavior.4 The authors defined fly biting as a syndrome in which a dog appears to be staring at something and suddenly snaps at it.
Each dog in this case series had complete medical and behavioral histories collected in addition to undergoing physical and
neurologic examinations. All the dogs were filmed during the behavioral assessment and for two hours after a meal to evaluate
characteristics of the fly biting behavior. A complete blood count, serum chemistry profile, and urinalysis were performed
in all dogs, and if there was a history of GI signs, a complete GI evaluation was performed. The behavioral histories of these
dogs revealed that the fly biting behavior had been present from six days to four years before the study and that the behavior
occurrence ranged from once daily to once every hour.
The video analyses revealed that all dogs raised their heads and extended their necks before fly biting, which may suggest
esophageal discomfort. All dogs in this case series were diagnosed with a GI abnormality, and one dog was also diagnosed with
Chiari malformation (a mismatch in volume between the caudal brain structures and the caudal skull associated with herniation
of the cerebellum through the foramen magnum5).
Six of the seven dogs responded to medical treatment alone, four with complete resolution of the fly biting behavior. No psychoactive
medications were administered concurrently with treatment of the medical issues.