Westie Armadillo Syndrome in Dogs

Along with the abnormal growth of the outer layer of skin cells, Westie Armadillo Syndrome also seems to be brought about, or aggravated, by an overgrowth of the naturally occurring yeast Malassezia. This budding yeast is a normal inhabitant of a dog’s skin, and most often lives in the ear canal, lips, anus, and between the digits in the paws.

When the conditions are right, this yeast can overpopulate, resulting in inflamed and itchy skin. While a Malassezia infection can be the primary cause of dermatitis, it is more commonly secondary to another condition. West Highland White Terriers are one of several breeds of dogs that seem to be predisposed to this type of infection. 

Westie Armadillo Syndrome refers to a skin condition affecting West Highland White Terriers. Also known as epidermal dysplasia, this abnormal skin growth results in itchy and thickened skin that can cause skin folds in various areas of the body. While it can occur at any age, it typically begins in puppies around 2 to 6 months old.

While this condition often begins in young puppies, it can be up to a year before the symptoms are obvious. Greasy and scaly skin becomes intensely itchy, and can cause your dog to scratch. Over time, the skin can become severely inflamed, resulting in crusts, scales, and darkened or thickened areas. While it can occur anywhere on the body, most commonly affected areas include the face, neck, abdomen, groin and tail. Signs that your dog may be affected include:

• Itchy skin
• Excessive scratching
• Skin inflammation
• Reddened skin
• Oily or waxy discharge from the skin
• Thickened and leathery skin
• Skin scaling 
• Skin folds
• Hair loss
• Darkened patches of skin
• Severe skin abrasions and crusts resulting from self-trauma
• Skin flaking
• Greasy coat
• Ear infections

The cause of Westie Armadillo Syndrome is believed to be due to an overgrowth of the Malassezia yeast. This overgrowth causes the yeast to become opportunistic and can lead to an infection in the skin that induces rapid and abnormal skin cell growth. Researchers believe that West Highland White Terriers may be predisposed to a Malassezia infection because of an inherited autosomal recessive gene that causes an allergy to this infectious agent. This allergy can cause an impaired skin barrier and an increased immune response to the presence of the yeast.

Other reasons why the Malassezia yeast may begin to proliferate include:

• Alterations in the quality of sebum
• Break in the skin barrier
• Accumulation of moisture on the skin

If you have noticed your dog scratching excessively, or other symptoms of this condition, your veterinarian will perform a physical exam to see which areas of your dog’s body are being affected and how severe the irritation is. A diagnosis is made after various tests to determine if there is an infectious agent, allergy, or other reason behind the skin irritation. 

Blood may be drawn for blood and serum testing. Skin scrapings, skin debris smears, or biopsies are taken and tested, and can show the presence of epidermal dysplasia and any infectious agent. Clear tape strips may be applied to affected skin areas and examined, which can reveal the presence of the Malassezia organisms. Your veterinarian may also perform intradermal allergy tests to determine if your dog has a specific allergy to the Malassezia yeast. If the ears are being affected, your vet may also take a sample of any debris in the ear for testing as well. 

Westie Armadillo Syndrome can be a difficult condition to treat. While therapies can help some of the symptoms, none that are available can cure this condition. Some affected dogs will experience periods of normalcy followed by flare-ups, and will need treatments intermittently. Most dogs, however, will suffer from constant dermatitis and Malassezia yeast overgrowth, and will need more frequent and lifelong treatment. Therapies include:

Topical Treatments

Bathing your dog in special shampoos, such as sulfur-salicylic acid, benzoyl peroxide, antifungal, or antiseborrheic shampoos, can be helpful in killing the yeast and soothing your dog’s skin. Ear medications and flushes are prescribed in cases when your dog is experiencing an ear infection. 

Medications 

Antifungal medications are generally given to control the yeast infection. While many of the symptoms tend to resolve with 30 to 45 days of this treatment, once it is stopped, the condition usually returns. Sometimes, an immunosuppressant is prescribed once the yeast overgrowth is under control. Your dog may develop a secondary bacterial infection due to the scratching, and may need antibiotics. Anti-inflammatories such as prednisolone may also be prescribed to reduce skin inflammation. 

Immunotherapy 

Allergen-specific immunotherapy (ASIT) may also be used to reduce your dog’s allergic response to the Malassezia yeast. This is given in the form of small concentrations of the yeast that are injected into your dog over a period of many months.

Medications will be given for you to administer to your dog, and special shampoos will be needed to bathe him in regularly. If your dog has a concurrent ear infection, you may also need to administer ear medication and clean his ears frequently. Resolution of symptoms has been seen in 6 weeks of treatment. 

Recovery depends on how early the condition is caught and treated. Younger dogs who undergo treatments can have a good prognosis, as long as the growth of the Malassezia yeast can be controlled. The longer the time between the onset of symptoms and treatment occurs, the more guarded the prognosis is. While treatment can help to resolve symptoms and return skin to its normal state, often the condition returns once treatment has stopped. Many dogs will need lifelong care. In severe cases, euthanasia can be recommended. 

Due to the possibility of an inherited predisposition for this condition, prevent this disease from affecting future generations of West Highland White Terriers by refraining from breeding affected dogs.