Skin

Acral Lick Dermatitis

OVERVIEW: 

 

Acral lick dermatis (ALD) is a frustrating self destructive condition that may or may not have a legitimate physical cause. The complexities associated with this condition and the fact that it can be the result of either legitimate physical injury or an unknown psychosis have led to the creation of many terms to describe this condition. These terms include canine neurodermatitis, acral pruritic nodule, acropruritic nodule, lick granuloma, acral lick granuloma and acral mutilation syndrome.  Defined literally, Acral lick dermatitis (ALD) is the inflammation of the skin on a limb or other extremity due to licking. Although this can accurately describe the end result; this technical definition fails to accurately describe the psychological or behavioral aspects that can be associated with this condition.

 

Also commonly referred to as lick granuloma or canine neurodermatitis both  of these as well can be misnomers. A granuloma as it is defined is an area of inflammation in tissue due to injury, such as from an infection or in the case of ALD licking. Thus it is actually a description of the end result of the behavior and not of the behavior itself. While canine neurodermatitis; is the general term used to describe a noncontagious inflammation of the skin presumed to be the body’s response to prolonged vigorous chewing, licking, scratching or rubbing to relieve severe itching believed to  originate in the mind. Neuro (dealing with the mind) and dermatitis (inflammation of the skin) is the only description that ads to the condition a mental or behavioral aspect although it fails to leave open the possibility of underlying physical causes.

 

The most appropriate definition for this condition would be; the manifested physical result of the behavioral act of incessantly licking or chewing a targeted area to the point of self mutilation due to either an underlying physical cause or as the result of an unknown psychosis.

 

Often times acral lick dermatitis is considered to be the result of a stereotypy or self-stimulatory behavior that is repeated without variation and for no apparent reason.  Research into animal stereotypies shows that in many instances, it is a maladaptive psychological behavior that can be induced by environmental factors such as stress or prolonged confinement.  Examples of stereotypical behaviors include pacing, rocking, walking in circles, excessive sleeping, self-mutilation (including licking, chewing and excessive grooming), and mouthing or chewing at cage bars. Ultimately, stereotypical behaviors are believed to be caused by artificial environments that prevent the animal from satisfying its natural behavioral needs.

 

Acral lick dermatitis may also be symptomatic of a larger behavioral issue such as obsessive compulsive disorder (OCD). Which is recognized as a potentially dangerous medical condition in which the dog will engage in normal canine activities such as grooming, running, chewing in an abnormally repetitive, obsessive and self-destructive manner. It is interesting to note that dogs suffering from obsessive compulsive disorder often have a history of neglect or exposure to extremely stressful environments. As with the aforementioned stereotypic behavior it has been shown that dogs forced into prolonged periods of confinement with no form of physical or mental stimulation may develop OCD.

 

What is agreed by most authorities on the condition is that acral lick dermatitis is a behavioral disorder with many possible origins. The licking may start as the result of an underlying physical cause such as allergic dermatitis, arthritis, neuropathies, neoplasia, fungal infections and ectoparasites; or it may be completely psychogenic in nature.

 

It is theorized that dogs suffering from this condition derive pleasure from licking or chewing at their extremities. In cases where the cause is an underlying physical disorder the licking is a natural response to the injury; the relief the dog receives from this serves to reinforce the behavior and the licking will continue even after the underlying cause has been corrected. If the licking is psychogenic in nature, dogs will use the licking or chewing as a way to relieve stress or tension caused by factors in their environment such as excessive confinement, excessive physical punishment or abuse or the introduction of new people or animals into the home.  It is also believed that overly attentive or excessively nervous owners; owners with mother hen syndrome can create this nervous behavior in their pets.

 

With ALD this constant licking or chewing to relieve or release this nervous energy starts a viscous cycle of self mutilating behavior. Having gained the reward for the behavior by relieving stress; the behavior is reinforced and continues whenever the animal finds itself unable to cope. This psychogenic licking eventually leads to the legitimate physical medical problems of hair loss and skin irritation. The irritated skin becomes ulcerous and infected, which in turn causes the nerves in the area to become inflamed and itchy. So much so, that the only way to feel relief from this now physical condition is to continue licking the area. A vicious cycle then develops and the condition becomes chronic.

 

In dogs where incessant licking is observed; it is important that the behavior be stopped and that the affected area be examined for an underlying physical ailments.  If obvious trauma cannot be found it may be necessary to take the dog to the veterinarian where bacterial cultures, radiographs, histological examinations or other laboratory tests can be performed to look for and rule out underlying physical conditions such as:

 

  • Allergic Dermatitis – Inflammation that results from allergic contact with a specific irritant.
  • Arthritis – painful inflammation in the joints can cause excessive licking of the area. Since the licking will not cure the underlying problem it will continue, eventually causing significant skin lesions.
  • Neuropathies – The inflammation of nerves under the skin can cause discomfort that leads to excessive licking.
  • Neoplasia – Certain types of skin cancer can cause uncomfortable lesions that lead to chronic licking.
  • Bacterial or Fungal Infections – Blastomycoses,  Ringworm and other deep seated fungal infections can initiate the problem.
  • Ectoparasites – External parasites like Sarcoptic mange, commonly known as scabies or Demodectic mange (Demodecosis) can lead to ALD.
  • Foreign Bodies – Splinters, glass or some other foreign body lodged in or under the skin can cause excessive licking of the area the leads to ALD.

 

If testing reveals no physical cause for the behavior, then it is most likely psychogenic or psychological in nature and the result of stress or boredom factors.

 

Although, Acral lick dermatitis is more prevalent in large active breeds, small dogs may be affected as well. The most common large breeds to be affected with acral lick dermatitis are the Dalmatian, Doberman, Great Dane, Labrador Retriever, Irish Setter, Golden Retriever, Border Collie and German Shepherd Dog.

 

SIGNS & SYMPTOMS: 

 

The most consistent symptom of acral lick dermatitis in pets is excessive licking of the extremities, especially the front and rear legs for no apparent reason leading to ulcerative sores.

 

DIAGNOSIS & TESTS: 

 

Diagnosing ALD is not always a straight forward process as potentially non visible physical ailments have to first be eliminated from the equation before a pet can be diagnosed with ALD. The process of diagnosing acral lick dermatitis first begins with observation and testing of the affected area to eliminate physical causes. The most common procedures performed are:

 

  • Skin Scraping – Ectoparasites like demodex or scabies tend to create symptoms and lesions that mimic those found with ALD.
  • Fungal Culture – Lesions from Ringworm commonly look similar to ALD lesions.
  • Radiography – X-ray’s are used to rule out the possibility that the licking is the result of a painful joint.
  • Skin Biopsy – provides a way to differentiate between deep fungal infections and skin tumors.
  • Fine Needle aspiration – a simpler alternative to an actual skin biopsy; a needle is used to take a small sample from the area and examined under a microscope.
  • Bacterial Culture – performed on sterile biopsy samples and used to eliminated bacterial infections as the cause of the lesions.
  • Allergy Testing – Allergic reactions can be one of the triggers for ALD.

 

Diagnosis is also made more difficult by the fact that acral lick dermatosis generally starts to develop at 5 years of age or older. Which means that the first clinical signs or lesions may coincide with seasonally related allergens like pollens.

 

The breed of dog also need to be taken into account as it is known that certain breeds have a higher propensity toward ALS than others.

 

Acral lick dermatitis has also been shown to be linked to hypothyroidism in some cases, especially with black Labrador retrievers; often times thyroid medication will resolve the issue if it is related to hypothyroidism.

 

CONVENTIONAL TREATMENT & MANAGEMENT: 

 

Unfortunately, Acral lick dermatitis is very difficult to treat with an overall success rate of only about 65%. Thus the prognosis is considered to be guarded.  Although, there are numerous types of treatment available, none have proven to be consistently effective in the treatment of this condition.  There are essentially two steps that need to be taken the heal dogs suffering from this condition; treating the wound and modifying the behavior which may include determining the source of any underlying stressors in its environment.

 

The first step is to treat the primary physical cause of the condition; if one exists. Depending upon the physical ailment topical medications such as corticosteroids may be effective if used very early on to help heal the lesion. A small lesion may be treated with injections of triamcinolone or methylprednisolone.  Oral antibiotics such as Cephalexin, Primor, Baytril and Clavamox are often used to prevent infection and lessen the risk of further medical complications.  Surgical procedures for removing whole lesions and injured tissue include surgical excision; radiation therapy, cryosurgery (freezing the lesion) and laser surgery (obliterating the lesion). Whichever treatment is used; it is important that the wound be protected from further aggravation through the use of restrictive collars, specialized bandages or nasty tasting sprays. It is also important to note that the behavior must be addressed; as many dogs will create a new lick granuloma, by licking at another leg, if they are prevented from licking at the original one while it heals. 

 

In cases where acral lick dermatitis is stress or anxiety related; behavior modifying and anti-obsessional drugs (antidepressants, antianxiety, etc.) including doxepin, amitriptyline, fluoxetine, and clomipramine are generally used in conjunction with treatment of the wound. Endorphin blockers such as naltrexone have also shown to be useful in reducing the addiction to licking. Endorphin substitutes such as hydrocodone may also decrease the urge to lick.  This is not to be confused with addressing the underlying stressors for the behavior but only serves to minimize the existing behavior through drug therapy. If the underlying psychological factors are not properly addressed and corrected, dogs usually relapse after the drugs are discontinued.

 

Although,  each of the above treatments have varying degrees of success and failure on a case by case basis; none of them address the stressors or triggers that serve as the origin for the disorder. Most will have short term success, but after removal of the bandages or stoppage of the medication, the behavior and self-mutilation will almost always begin again. This is why it is so important to address the source of the behavior and couple that treatment with one of the above if there is any hope for success. Observe the animal’s environment to see which stimulus is causing the dog to suffer from anxiety. Questions the owner need to ask themselves is:

 

  • Is the dog a breed with strong pack mentality but being socially isolated with little or no human contact?
  • Does the dog find itself crated for hours on end while the owner is at work?
  • Is the dog home alone over eight hours a day?
  • What kind of exercise is the dog receiving?
  • Is the dog an active breed being forced to live a sedentary lifestyle?
  • What other emotional or physical needs does the dog have that are not being met?

 

Healing the emotional scarring is in many cases more important the healing the physical ones in order to treat acral lick dermatitis. Remember treatment for this condition involves removing the stimulus and modifying the behavior while medically treating and protecting the self induced lesions from further injury while they heal.

 

POTENTIAL COMPLICATIONS: 

 

In most cases, acral lick dermatitis is an extreme annoyance for the owner but does not pose a serious risk to the health or well-being of the dog. However, acral lick dermatitis does tend to be a chronic, long-term problem that can cause many owners of dogs with this syndrome to become frustrated.


In rare cases, dogs with severe acral lick lesions can suffer from severe skin infections and their related complications as well as pain, chronic lameness and discomfort.


 

HOLISTIC REMEDIES: 

 

Holistic remedies for Acral Lick Dermatis should be aimed at treating the symptoms of the condition such as lesions and hair loss or lessoning certain behaviors known to cause the condition such as nervousness or anxiety. These are not to be considered a cure as the only true cure for this condition is to seek out, isolate and remove the causative stimuli while working on behavioral modification to prevent it.

 

This is not to say that holistic or homeopathic remedies will prove ineffective only that the owner should be mindful of the fact that there may be underlying physiological or behavioral issues that may lessen their effectiveness. 

 

Contrary to typical western medicine which advocates the use of high priced prescription medications, there are a variety of natural plants, herbs and other treatments that have been in use for centuries by other cultures for the treatment of both skin and personality related ailments. Herbs such as German Chamomile (Matricaria recutita) also spelled Camomile have shown to provide significant relief in the form of an anti-inflammatory to soothe  the itchy and irritated skin associated with Acral Lick Dermatitis. It may also provide some benefit in soothing the animal and/or preventing the nervous behavior known to lead to ALD, as it has also found widespread use as an herbal sleep aid in humans. Modern studies have also demonstrated that Chamomile has shown effectiveness in speeding the healing time of wounds in animals and providing some benefit in the animal model of diabetes.

 

Other holistic remedies for Acral Lick Dermatitis may include Cleavers (Galium aperine), a ground creeping plant native to North America and Eurasia. Traditionally Cleavers has been used as a Poultice and wash to soothe and speed the healing of light wounds and burns. As a tonic it has found use in expelling toxins from the body providing assistance in the treatment of skin conditions like eczema and allergic dermatitis. As a pulp, it has been used to relieve the discomfort associated with poisonous bites and stings.

 

As with Chomomile, Clevers may also provide a soothing effect which will help abate the nervous behavior that can lead to Acral Lick Dermatitis. The asperuloside in cleavers acts as a mild sedative, and has shown the ability (as an extract) to lower the blood pressure of dogs, without slowing their heart rate, or any other dangerous side effects. The only published dosing information comes from Ethnobotanist Dr. James A. Duke who recommends a human dosage of one ounce of dried leaves to a pint of water, 1 to 2 teaspoons of tincture, or 2 to 4 grams of the dried herb in a cup of boiling water, three times daily.

 

Other plants that may provide some relief include Marigold (Calendula officinalis) and Witch Hazel (Hamamelis virginianum) which can reduce swelling and have shown themselves to be very effective in soothing the itchiness associated with Acral Lick Dermatitis. 

 

PREVENTION & HELPFUL TIPS: 

 

  • Always ensure the dog is getting plenty of exercise, not just being left to its own devices while isolated the yard. Exercise should include mental as well as physical stimulation. Activities like taking a walk together, playing fetch, and tug o rope are good examples of exercises that stimulate the mind as well as the body.
  • Enroll the dog in obedience classes or participate in other dog related sports such as agility, dock diving, Frisbee or flyball. Activities that include other dogs give your dog the chance to socialize and provide plenty of mental stimulation.
  • If your situation means that the dog will be home alone 7-8 hours per day, have a friend take the dog for a walk or get another dog to provide some company. Dogs are social beings and natural pack animals; being forced to be alone for prolonged periods is unnatural, stressful and an unhappy situation for a dog.
  • Always choose a dog that is suitable for the lifestyle it is going to have to live. If you are active choose and active breed, if you’re a sedentary individual then choose a dog that likewise enjoys lounging around.

 

Not only will the above help to increase the bond between dog and owner; but they will decrease the stress and anxiety that can lead to many behavioral disorders like canine acral lick dermatitis.

 

 

Discoid Lupus Erythematosus

 

Discoid Lupus Erythematosus is an uncommon autoimmune disease of the skin in dogs. It does not progress to systemic lupus erythematosus in dogs. The most common initial symptom is scaling and loss of pigment on the nose.

 

Ehlers-Danlos-Like Syndrome

 

Dermal Fragility Syndrome, also known as Ehlers-Danlos-like syndrome, is a rare condition in dogs characterized by increased skin elasticity and poor wound healing. There appears to be a genetic basis for the disease.

 

Follicular Dysplasia

 

Follicular Dysplasia is a genetic disease of dogs causing alopecia, or hair loss. It is caused by hair follicles that are malfunctioning due to structural abnormality.

 

Juvenile Cellulitis

 

Leiomyosarcoma is a relatively rare form of cancer, comprising between 5-10% of soft tissue sarcomas, which are in themselves relatively rare. Leiomyosarcomas can be very unpredictable. They can remain dormant for long periods of time and recur after years. It is a resistant cancer, meaning generally not very responsive to chemotherapy or radiation. The best outcomes occur when it can be removed surgically with wide margins early, while small and still in situ.

 

Lick granuloma

 

See Acral Lick Dermatitis

 

Pemphigus

 

Pemphigus is an uncommon autoimmune skin disease. The most common form in dogs is pemphigus foliaceus, which manifests as erosions and crusting of the skin and mucocutaneous junctions. Pemphigus vulgaris is more rare and manifests as blister-like lesions in the mouth and at mucocutaneous junctions. Bullous pemphigoid is most commonly seen in Dobermans and Collies and appears as a scald-like lesion of the groin.

 

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