Dog exhibiting excess licking behavior. Minertree/iStock
Stereotypic behaviors such as fly biting, stargazing, and excessive licking of surfaces are not uncommon presenting complaints for patients being evaluated through the Neurology Service. Many times patients exhibiting these behaviors are referred to a neurologist due to the concern for seizure activity or to a behaviorist due to the concern for obsessive compulsive disorders. However, underlying primary gastrointestinal (GI) disease should not be overlooked as a potential cause for these behaviors.
Several studies have been published over the last few years in reference to primary GI disorders in dogs manifesting as stereotypic behaviors such as excessive licking of surfaces or fly biting. In a prospective clinical study out of Canada, underlying GI abnormalities were noted in 14 out of 19 study dogs with a history of excessive licking of surfaces. In this study by Bécuwe-Bonnet et al., all dogs included in the study underwent physical and neurologic examinations by board-certified specialists. Following examinations, bloodwork was collected for complete blood count, serum chemistry panel, pre- and post- bile acids, and canine specific pancreatic lipase immunoreactivity. Fecal and urinary samples were also submitted for evaluation. In addition, each study dog had a standard upper GI endoscopy performed under general anesthesia and mucosal samples were collected from various areas of the stomach and duodenum. Study dogs were also videotaped for additional behavioral evaluation. Specific treatment was recommended and started in the 14 affected study dogs with a specific GI disorder based on diagnostic test results. For the 5 study dogs with excessive licking behavior that did not have a specific GI disorder, nonspecific treatment such as an elimination diet and antacid were started. Study dogs were then monitored for 90 days following treatment initiation. Almost 60% of dogs with excessive licking behavior were noted to experience significant improvement in the frequency and duration of their behavior with treatment. Over half of the dogs in the study with excessive licking behavior had complete resolution of their clinical signs with treatment. Based on the findings in this study, GI disorders should be included on the list of differential diagnosis in patients presenting with excessive licking behavior.
A similar prospective study by Frank et al. looked at 7 dogs with fly biting behavior and found GI disease in 5 of the 7 dogs. Dogs in this study were treated with a combination of an elimination diet, Famotidine, Fenbendazole, Prednisone, Metronidazole, Sucralfate, and/or a prokinetic agent. Five of the seven dogs improved and 4 of the 7 had a complete resolution of fly biting behavior after 30 days. Both the Bécuwe-Bonnet and Frank studies identified repeatable stereotypic behavior, specifically excessive licking and fly biting, associated with primary GI disease, which is similar to Sandifer Syndrome observed in infants and non-verbal children. Sandifer Syndrome is a rare movement disorder characterized by spasmodic torticollis and dystonia, such that patients will have episodes where they will arch their back and hold their neck in marked extension for several minutes. Sandifer Syndrome is associated with underlying gastroesophageal reflux disease (GERD) and successful treatment of GERD with antacid therapy leads to suppression of dystonic movements and resolution of clinical signs. It is believed that the dystonic movements observed in children with Sandifer Syndrome are a vagally mediated response to esophageal pain and discomfort. The same theory may also apply to dogs with esophageal and/or upper GI tract disease and secondary discomfort that present with excessive licking or fly biting behavior.
In practice, for patients that present to me with clinical signs of excessive licking, star gazing, and/or fly biting with an otherwise normal neurologic examination, I have GI disease on my list of differentials. I typically recommend a trial of Omeprazole at 1 mg/kg PO Q24hr for 2-3 weeks, particularly in patients with a history of repetitive neck extension and/or clinical signs that appear to be worse after meals. During this time, I will ask owners to monitor for a decrease in the frequency and duration of their pet’s episodes. Depending on the patient’s medical history, physical exam findings, diagnostic test results, and my suspicion for partial seizure activity, I may also place these patients on a trial of anti-seizure medication, such as Levetiracetam (20-30 mg/kg PO Q8hr) or Zonsiamide (5 mg/kg PO Q12hr), at the same time or following the Omeprazole trial if no improvement is noted. Additional diagnostic work up for primary GI disease (ex. bile acids, endoscopy, etc.) and/or neurologic disease (ex. MRI of the brain +/- spinal tap) may be warranted depending on the patient’s response to therapy and progression of clinical signs. It should be noted that Omeprazole not only increases gastric pH but has also been shown to decrease the production of cerebrospinal fluid. Therefore, it is used routinely for treatment of esophagitis and gastritis, but is also used in the management of caudal occipital malformation syndrome (COMS) and syringomyelia (SM). It is possible that some patients who respond favorably to Omeprazole therapy may be benefiting from not only its antacid effects, but also from its effect on CSF production.
In summary, when presented with stereotypic behaviors such as excessive licking, fly biting, and stargazing in a canine patient, primary GI disease should be on your differential list, as many patients may respond favorably and even experience a complete resolution of clinical signs with proper treatment.
For more information, please contact Angell’s Neurology Service at 617-541-5140 or Neurology@angell.org.
Bécuwe-Bonnet V, Bélanger MC, Frank D, Parent J, Hélie P. Gastrointestinal disorders in dogs with excessive licking of surfaces. Journal of Veterinary Behavior 2012; 7: 194-204.
Frank D, Bélanger MC, Bécuwe-Bonnet V, Parent J. Prospective medical evaluation of 7 dogs presented with fly biting. Can Vet J 2012; 53: 1279-1284.
Poirier-Guay MP, Bélanger MC, Frank D. Star gazing in a dog: atypical manifestation of upper gastrointestinal disease. Can Vet J 2014; 55:1079-1082.