Lick Granuloma

A very frustrating skin disease found mostly in dogs is called acral lick dermatitis (ALD), commonly know as a lick granuloma. Dogs with this disease lick incessantly, causing chronic skin lesions of the limbs.

Many aspects of ALD are similar to allergic dermatitis in general. This page will give you an opportunity to link to the aspects of the allergic dermatitis page that also apply to ALD.


 

Pathophysiology

Constant licking leads to hair loss and irritation of the skin. As the problem progresses the skin becomes ulcerated and infected. As the ulceration progresses nerves become inflamed and the area becomes pruritic (itchy), so much so that the dog can not stop licking. A viscious cycle develops and the condition becomes chronic.

It is theorized that some dogs get into such a licking habit, and actually derive pleasure from it, that once the initiating cause is eliminated they still continue to lick.


 

Cause

This is a disease that has many factors involved with the cause. Some of these work in combination, adding to the complexity of the problem. In some breeds, notably Doberman pinschers and Great Danes, the cause might not be found. The most common causes include:

Allergic Dermatitis

This is considered the primary cause of the problem. We have a detailed page on allergies to learn more about this complex problem. Food allergy is a component of this also.

Arthritis

Joints in the area of the lesion can be painful, causing excessive licking of the skin over the area. Since the licking does not cure the problem, it continues, eventually causing significant skin lesions.

Neuropathies

Inflammation of the nerves under the skin in the area of the lesion can cause significant discomfort, again leading to excess licking.

Neoplasia

Skin cancer can cause chronic lesions that are uncomfortable and lead to chronic licking.

Fungal Infections

Deep seated fungal infections, including blastomycoses and Ringworm can initiate the problem.

Ectoparasites

External parasites like scabies and demodex are also potential causes.

Psychogenic

This is a catch-all term for psychological causes that are thought to be involved. They include boredom and stress factors. Similarities have been made between this and obsessive-compulsive disorders in people. When you see a dog licking incessantly at his legs you can see why this comparison is made. 


 

Symptoms

The most consistent symptom in pets with ALD is excessive licking of the extremities, especially the front and rear legs. Lameness could occur due to infected skin or even arthritis. If the skin infection is serious enough there might be a lack of appetite (anorexia) or lethargy.


 

Diagnosis

The correct diagnosis for ALD does not come easy, so a thorough approach is needed. In every disease we encounter we follow the tenet’s of the diagnostic process to ensure that we make an accurate diagnosis, and that we do not overlook some of the diseases that are also encountered in pets as they age.

1. Signalment

Several breeds are prone to ALD:

  • Doberman pinscher
  • Great Dane
  • Golden retriever
  • Labrador retriever
  • German shepherd
  • Boxer
  • Dalmatian
  • English Setter
  • Shar Pei
  • Weimaraner

2. History

ALD usually starts appearing when dogs reach at least 5 years of age, especially the above breeds. When it first appears it might coincide with allergy symptoms that are seasonal in nature.

3. Physical Exam

This is a picture of the classic finding in a dog with ALD.


 

If the skin infection is severe enough there might be swelling (cellulitis) due to the infection. Also, the lymph node that drains the affected area might be enlarged and there might even be a fever.

4. Diagnostic Tests

Diagnostic tests are important since many skin conditions look the same, even though they have different causes and are treated differently. In some situations other skin diseases can occur simultaneously with ALD.

Skin Scraping

It is important to do a skin scraping in many cases of ALD because the symptoms and lesions commonly mimic those of ectoparasites like demodexor scabies.

Fungal Culture

Ringworm lesions can look similar to ALD lesions. In Ringworm there is usually not as much licking.

Radiography

If we suspect the licking is from a painful joint we can sometimes make this diagnosis from an x-ray.

Skin Biopsy

This test is used to help differentiate skin tumors or deep fungal infections as the initial cause of ALD.

Fine Needle aspiration

As an alternative to an actual skin biopsy we can do a simpler test called a fine needle aspirate. In this test we use a syringe with a tiny needle to take a sample of the affected area. This sample is put on a microscope slide for analysis by one of our pathologists.

It does not require general or local anesthesia and can be performed during an office call. Only a small amount of tissue is sent to the lab for analysis, so it is not always possible to make a complete diagnosis this way.

Bacterial Culture

This test will give us an indication of the type of bacteria involved. Staphylococcus and Enterobacter are the more common pathogens. Since the top of the lesion is contaminated with many bacteria, some of which are not part of the problem, a culture is performed on biopsy samples that are taken in a sterile manner.

Allergy Test

Allergies can be a major component of ALD. Please refer to our allergic dermatitis page due learn about allergy testing.


 

Treatment

ALD tends to be a chronic disease that leads to significant frustration. The wide variety of treatments that are used to treat ALD are an indication of the complexity of this disease and the fact that many different causes, some working in tandem, are involved.

Flea Control

We can not emphasize the importance of proper flea control in any pet that has a skin condition since we live in a flea endemic area year round. Even pets that are 100% indoors are possible flea victims.

The products available today are a significant improvement over flea control products in the recent past. They are economical, safe, effective, and very convenient. The two main products we recommend are Trifexis for dogs© and Revolution for cats©. We have detailed brochures on each to explain how they work, please ask one of our receptionists. In addition to treating fleas they prevent heartworms and treat parasites.

Anti-inflammatories

Cortisone is used initially to minimize swelling and licking. It is not used as the primary means to control ALD in the long term since a skin infection is almost always present and cortisone decreases the immune system’s ability to fight this infection. Cortisone is used much more often in treating allergic dermatitis. There is a section there on its proper use.

As an option to using cortisone to minimize the licking we suggest the use of elizabethan collars. A good option that is tolerated well by larger dogs is a small plastic bucket with a hole cut out of the bottom that is placed over the head.

Antibiotics

Oral antibiotics are the most important treatment we have for ALD. In some cases we need to use them for 4-6 months due to the chronic nature of the problem. It is important to continue them for at least 3 weeks after the skin looks healed. In some pets we put them on intermittent antibiotic therapy for the rest of their lives- this is called pulse therapy.

Antibiotics that work best include:

  • Cephalexin
  • Primor
  • Baytril
  • Clavamox

Laser Therapy

We have had success using our laser machine in the treatment of this problem. It usually takes at least 3 treatments, and in some cases can be a significant help in minimizing the licking.

This Labrador has an ALD lesion on top of its rear foot area. It is been prepped or laser treatment.


The laser is being used at a light setting with an intermittent pulse.

 


The appearance of the lesion immediately post laser treatment.

Pain Medication

Initially it is useful to put your pet on pain medication until the antibiotics and other treatments start working. NSAID’s like Rimadyl can because because they decrease inflammation and also pain. Tramadol can also be used initially.

Antifungals

If a deep seated fungal infection is diagnosed we will use oral fungal medication for an extended period.

Allergy Shots

This can be a good way to minimize itching without using cortisone. The less we use cortisone to minimize itching the faster the problem will resolve. These are injections give on a long term basis, usually once per month once the allergy is improving.

Food allergy

We recommend feeding hypoallergenic diets to any pet that has a skin condition caused by an allergy.

Food Supplements

Some allergic dogs and cats scratch less when supplemented with essential fatty acids. The main ones we use are Derm Caps and EFa-Z.

Surgery

This is not a rewarding way to treat ALD since the problem commonly recurs after the surgery.

Topical Medications

It is a natural tendency to want to use topical medication only on a skin problem. If used in combination with long term oral antibiotics this topical medication can be beneficial. They are not effective when used alone.

Behavioral Modification Medications

Some dogs are compulsive lickers without any obvious cause. Some veterinarians believe that the incessant licking in ALD is similar to the exaggerated grooming habits of people with obsessive-compulsive disorders.

These medications are helpful, but do have the potential to cause side effects, especially when used with other medications. One of our doctors will let you know if they apply in your situation.

Veterinary Neuronal Adjustment

An additonal treatment modality used to treat ALD is VNA. It is a non-invasive and non-painful way to stimulate the nervous system to stop the sensation that is causing the problem.


 

Prognosis

ALD has a guarded prognosis. An early and accurate diagnosis (when one is apparent) offers the best option by instituting proper medication before the problem becomes so chronic that treatment is only marginally effective.