There are many potential physiological and psychogenic causes of excessive licking and chewing behavior. When the licking and/or chewing is focused on the elbows or the paws, which is common, the condition can be medically categorized as a lick granuloma or acral lick dermatitis. In less severe cases of lower limb licking, the behavior is intermittent and harmless to the coat and skin. In such cases, treatment is non-essential. However, in more severe cases, physically the licking and chewing cause temporary or permanent alopecia (hair loss) and problematic secondary dermatic infection and psychologically the behavior becomes obsessive-compulsive, whereby the dog’s attention to the behavior interferes with his/her ability to engage in normal lifestyle activities, such as eating, play, or social interaction.
The first step in treating any behavioral condition is accurately diagnosing the cause. Although excessive licking and chewing of the paws most frequently has a primarily psychological origin, often enough the behavior has a primarily physiological etiology, where the behavioral condition is secondary to the primary physical cause. Therefore, the first step should be a trip to your veterinarian for a thorough examination.
1) Potential Physiological Causes:
- Bacterial Infections (Pyodermas)
- Contact Allergies or Irritants
- Dry Skin (Xeroderma)
- Flea Allergy Dermatitis
- Food Allergies
- Fungal Infections
- Hyperadrenocorticism (Cushing’s Disease)
- Inhalant Allergies or Irritants (Atopy)
- Joint Pain
- Liver Abnormalities
- Lupus Erythematosus
- Neurological Conditions
- Pharmaceutical contraindications
- Pruritus (Itching)
As you can see, there are many potential physiological causes of excessive canine licking and chewing. Therefore, unless the correct diagnosis is salient and quickly obtainable, your veterinarian should perform a thorough examination, not merely a cursory inspection. Moreover, if your regular veterinarian is unable to diagnose a cause and behavioral solutions fail to achieve optimal results, then you may wish to seek the services of a board diplomated veterinary dermatological and immunological specialist who concentrates on such conditions.
2) Potential Psychogenic Causes:
Although we advise clients to first obtain a veterinary examination before undertaking a behavioral solution, the majority of cases where a dog’s licking or chewing behavior is localized to the paws are primarily psychogenic in origin. Nevertheless, even when the origin is psychological, compulsive licking or chewing behavior can quickly progress to a stage where there is physical tissue damage and veterinary treatment is required. Below we list the most common psychogenic origins of excessive licking or chewing of the paws.
- Attention Seeking Behavior- Owners may inadvertently reward dogs with attention whenever they lick or chew, which in turn ironically provokes the dog to lick or chew more frequently in an attempt to seek greater attention.
- Boredom- Dogs that are bored may begin to lick or chew their paws to provide themselves an activity or to out of habit commence an action that improves their emotional state via a release of dopamine and opioid neurochemicals.
- Depression- Depressed dogs may begin to lick or chew their paws to create the anti-depressant effects created by the natural release of dopamine and opioid neurochemicals.
- General Anxiety Disorder- Dogs that are generally anxious may lick or chew their paws to release nervous energy or to obtain a more relaxed emotional state via the release of calming or satisfying neurochemicals.
- General Understimulation- Excessive confinement, a dull home environment, loneliness, lack of walks, lack of exercise, lack of mental stimulation, a lack of chew or play toys, or a general lack of sensory stimulation may result in depression or anxiety, whereby the dog begins to compensate by licking or chewing its paws.
- Habit- Paw licking or chewing may commence due to a physical etiology, but remain a behavioral problem after the physical origin is resolved, due to the formation of habitual behavioral patterns.
- Obsessive-compulsive Behavior- An obsessive-compulsive status occurs when the dog’s incessant licking or chewing interferes with normal lifestyle activities, such as eating, playing, socializing, or sleeping. In such a case, the dog may be unable or unwilling to cease the behavior without overt extrinsic modes of prevention, interruption, or diversion.
- Obsessive-compulsive Self-grooming- In some cases the behavior starts as normal self-grooming behavior, but becomes abnormally habitual, excessive, and obsessive-compulsive, especially after the abraded area becomes sensitive, sore, or painful.
- Separation anxiety- Dogs that are distressed due to separation or isolation may begin to lick or chew their paws to expend nervous energy and create a more relaxed emotional state due to the release of dopamine and opioid neurochemicals.
- Stimulus-specific anxiety- A dog may begin to lick or chew its paws as a coping mechanism to relieve anxiety, stress, or tension resulting from a specific stimulus that the dog finds aversive, threatening, or unpleasant.
- Stress- Dogs that become generally stressed due to boredom, understimulation, depression, frequent exposure to an aversive stimulus, or a general anxiety may begin to lick or chew paws as a coping mechanism that both reduces systemic cortisol levels and increases systemic dopamine and opioid neurochemicals.
The first step in developing a solution plan is to properly diagnose the primary cause of the behavior. As stated above, we recommend first identifying or ruling out a physiological etiology. Moreover, even if there is a primarily psychological origin, if the behavior has festered, it is likely that veterinary treatment is required to heal tissue damage that has occurred from the weeks or months of constant licking or chewing- as the behavior is likely to recur if the wound remains untreated.
Conversely, if the behavior initially had a physiological origin and the behavior persisted, a habitual or obsessive-compulsive behavior may develop that remains past the time when the physical injury, disease, or condition is effectively treated. Consequently, in many cases both physiological and behavioral solutions will be required.
As with many behavioral problems, we prefer to incorporate a trifurcated (3-prong) solution strategy. The first prong addresses the origin(s), figuring that if the cause of the behavior is effectively addressed the behavior should extinguish soon after. The second prong is preventive, as we must discontinue access to the behavior for the dog to break a behavioral habit that the dog may perform both consciously and unconsciously. The third prong is symptomatic. The symptomatic prong provides interrupters and aversive conditioners that impede the behavior or that create an unpleasant association with the behavior. The symptomatic prong also provides diverters and positive reinforcement that prompt the acquisition of mutually desirable alternative coping mechanisms that we hope will replace paw licking or chewing as the behavior of choice.
1a) Treating Physiological Origins:
Since this is an abstract and primarily a training and behavioral article, we will not delve into the area of veterinary solutions. If your dog’s licking/chewing is caused by a physiological origin or if psychogenic licking/chewing results in tissue damage that requires veterinary intervention, please consult directly with your veterinarian regarding the preferred mode of treatment.
1b) Treating Psychogenic Origins:
Depending on the specific psychogenic origin, solutions may include:
- Modifying owner behavior by encouraging the owner to ignore the dog’s licking and chewing behavior and to instead pay attention to the dog only when he/she is not licking.
- Proactive stimulation (walks, play, rigorous exercise, and obedience or agility training or some other form of mental stimulation).
- More quality time with family members.
- Dog day care.
- Selecting more enticing chew and play toys.
- Making the yard more stimulating.
- Adding shade to the yard.
- Identifying trigger stimuli or stressors.
- Removing the stimulus or stressor from the dog’s environment.
- Removing the dog from the environment containing the stimulus or stressor.
- Desensitizing the dog to the trigger stimulus or stressor.
- Controlled flooding drills.
- Treating an underlying medical condition that may cause stress or pain.
- Dietary management.
- Administering homeopathic anti-anxiety remedies.
- Short-term administration of benzodiazepine medication (diazepam/valium, alprazolam/xanax).
- Long-term administration of tricyclic antidepressants or SSRI psychopharmaceutical medication (e.g., clomipramine/Clomicalm, fluoxetine/Prozac/Reconcile).
- Administering opioid receptor antagonists (naltrexone) or opioid receptor protagonists (hydrocodone, tramadol).
- Impulse control training.
- Leadership training (for the owner).
- Confidence building exercises.
- Re-ordering the owner’s departure routine.
- Desensitizing the dog to key elements of the owner’s departure routine.
- Modifying the sensory environment (visual, auditory, olfactory, tactile taste) to better relax the dog when isolated.
- Revising the enclosure environment.
- Developing a diversionary departure strategy.
- Implementing random departure behavior modification drills.
- Videotaping to ascertain which solution alternatives provide therapeutic outcomes.
Since many of the treatments listed above are too complex to include in detail within the scope of this article, we highly recommend consulting a CPT behavior modification expert when designing a treatment program for a dog exhibiting excessive licking/chewing behavior. The CPT professional will diagnose the behavioral origin(s), formulate the solution plan, and properly instruct you how to implement the plan, so that the probability of extinguishing the behavior is maximized.
2) Preventive Methods:
Regardless of the primary origin, prevention is imperative in accomplishing a successful behavior modification outcome. Without preventing access to the licking/chewing behavior, the habit will continue and we will not have the opportunity to totally eradicate all primary or secondary behavioral causes or to encourage the dog to successfully adopt a replacement behavior. There are several preventive alternatives.
- Elizabethan Collar
- Neck Donut
3) Symptomatic Methods:
Symptomatic methods attempt to make the paw licking/chewing behavior less palatable to the dog while concurrently encouraging the adoption of a replacement oral behavior. There are several types of symptomatic methods relevant to paw licking/chewing, including active diverters, passive diverters, interrupters/punishers, aversive conditioners, and positive reinforcers.
- a) Active Diverters- Active diverters include tug ropes, Kongs, tennis balls, soccer balls and games of chase with the owner. Active diverters occupy the dog mentally and physically, so that he/she does not have the opportunity to engage in licking/chewing behavior. To prevent inadvertent conditioning that may cause licking/chewing to become an attention seeking behavior, rather than prompting the dog to play after he is licking/chewing, preempt the dog by diverting him to play before he starts licking/chewing his paws.
- b) Passive Diverters- Passive diverters include antlers, sterilized bones, Kongs, nylabones, gumabones, pressed rawhide, and Buster cubes that the dog can chew on his own. In some cases (bones, kongs, Buster cubes) you can also place food inside the toy to occupy the dog. To encourage use of the passive diverter as a replacement behavior, praise your dog when you see him chewing with or playing with the selected diverter.
- c) Interrupters/Punishers- Interrupters are intended to prompt the dog to cease the licking/chewing behavior when you catch him in the act and to punish him, which by definition means that he will become less likely to repeat the behavior in the future. Interrupters include shouting “No”, spraying a squirt gun, and/or blowing an air horn. Of the three, we usually prefer the air horn. Nevertheless, despite the potential advantages of including interrupters/punishers in the overall behavior modification program, since anxiety is often a contributing cause of licking/chewing behavior, we prefer emphasizing preventive methods and/or passive aversive conditioners over interrupters/punishers that may inadvertently increase the dog’s general anxiety due to environmental stress arising from impending owner punishment or aversive noise.
- d) Aversive Conditioners- Aversive conditioners passively punish the dog, so that the dog finds the licking/chewing behavior unpleasant and reduces the frequency of the behavior into the future. Bitrix spray, Bitter Yuck spray, Bitter Lime gel, and Bitter Apple gel are often effective aversive conditioners, especially when applied atop a bootie or bandage and used in combination with an Elizabethan collar, a neck donut, or active supervision.
- e) Positive Reinforcers- Positive reinforcement is intended to reward the dog for performing a desirable replacement behavior, so that he/she is more likely to repeat the replacement behavior in the future, rather than continue to lick/chew his/her paws as a source of relaxation, pleasure, anxiety relief, or pain relief. Consequently, when you observe your dog independently selecting a passive or active diverter for oral stimulation, praise lavishly and even consider treating him.
© Copyright Mark Spivak and Comprehensive Pet Therapy, Inc., September 2010, All rights reserved.
Please note that the above article is written principally for informational purposes.