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Beaver Lake Animal Hospital
26325 SE 39th Street
Issaquah, WA 98029
(425)557-0752


Beaver Lake Animal Hospital

26325 SE 39th Street
Issaquah, WA 98029

(425)557-0752

www.beaverlakeah.com


Dermatitis


 

Dermatitis

 

General Information

 

Skin problems or dermatitis are common in veterinary medicine. Although the skin is on the outside of the pet, it can be very difficult to determine the instigating cause of dermatitis. It does not matter what is causing the problem, the skin reacts in much the same manner. It can become red, become itchy, lose the hair, become thicker, ulcerate, turn a darker color, or become more waxy, scaly or crusty.   There are usually patterns that we see in various skin diseases. These may be changes that can be subtle, or in advanced cases can be marked. It can be difficult to determine a primary lesion from a secondary effect. There can even be multiple diseases occurring at the same time on one animal.  Skin diseases have a variety of causes.  Genetics, allergies, parasites and infections are common causes.


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Many dogs suffer from allergies.  Unlike humans, dogs usually have troubles with their skin when they are exposed to allergens of any kind. The skin can come reddened and itchy. Common sites that are affected are the ears, axilla (armpit), the bottoms of the feet, the ventral abdomen and thorax, as well as the perineal and anal areas. In severe situations, the mucous membranes and gastrointestinal tract are affected, leading to gastroenteritis with vomiting and diarrhea. There are several categories of allergies. There are inhalant (known as atopy), food flea and contact allergies. Many allergic pets may have "mixed" allergies. If allergies are suspected, it is reasonable to test for the food and inhalant allergies in addition to controlling fleas.

 

            We are fortunate to live in an area with few common parasites other than fleas. Flea allergy is very common in dogs and cats. Although a normal dog or cat can deal well with several fleas on their skin, even one fleabite will initiate a chain reaction that can cause much distress for an allergic animal. You may think of this similar to people that are allergic to bee stings. Just a small sting can put a person's life in jeopardy. Although the type of allergic reaction is different, this demonstrates that only a little bite or sting can set off severe reactions.

Flea allergy is determined most frequently by a pattern of puritis (itching), redness and hair loss. On dogs, this is seen most commonly seen over the rump. On cats, it is more commonly seen around the neck and shoulders. Direct evidence of fleas includes finding the parasite, or the flea feces. However, this is not required to make the diagnosis.

Treatment for flea allergy is to keep the fleas from the pet. It is nearly impossible to keep a pet that goes outdoors from having a flea jump on board. Even the best treatments only kill fleas after they have jumped on the pet. So, even a pet that is as well protected as possible may still be bitten occasion. Please ask how we can help you with a flea control program.

 

Atopy is one of the most common types of allergies. With atopy, things that are inhaled are causing the problems. This is similar to how many people have allergies. Pollen, grasses, trees dust mites, and cat or dog hair are all examples of inhalant allergens. There are millions of these allergens. For animals that have only a few inhalant allergies, they may have problems only seasonally when the allergen is most prevalent.  In a season such as winter, there is less allergen in the outside air, and the allergic side effects subside temporarily unless the pet is allergic to indoor allergens such as dust mites. Many times, a dog may develop allergies after a geographical move. In truth, the pet is now exposed to different plants that they are sensitive to.

Atopy is one of the most common skin diseases we have to deal with.  It is estimated that 10- 15% of the canine population is clinically afflicted.  Atopic dogs typically will start to show signs within the first 3 years of life.  Some will show signs as early as only a few months old.  It is felt that genetics as well as environment play important roles in atopy.

Inhalant allergies are determined in one of two ways. Although there are millions of allergens, there are about 40 common allergens in Western Washington that we normally test for. The first and original way was with a skin test. I refer to a certified veterinary dermatologist for this. It may involve sedation or anesthesia and a day in the hospital.  The second way is through testing the blood.  This method has improved much in recent years. All it requires is a single blood sample that is sent in to a special lab. Within 1-2 weeks, the allergens that your pet responds to will be known. Whichever method is chosen, the allergens most common for this area are tested for. Once the allergens that your dog is sensitive to are identified, a serum can be made to begin hyposensitization. Hyposensitization may take 6 to 9 months to show the improvement or even longer in some cases About 80 % of atopic pets will benefit to some degree by hyposensitization. About 60 % of pets undergoing hyposensitization will be controlled without the need for cortisone. The remaining pets may still need cortisone on occasion, but should need less than without hyposensitization. Our goal is to help as many pets to be as comfortable as possible with minimal use of cortisone.

Click on the file at the bottom of this page for more information on allergy testing and hyposensitazation.

 

Food is a common source of allergens for animals.  It is a common misconception to think my pet has been on this food for years, he cannot be allergic to the food'.  But, animals can and do acquire allergies, so the food they have been on, may be a source of allergy.  The protein in the food is the main allergen culprit for most pets. Some pets are sensitive to the preservatives. Many people feed their pet Lamb and Rice' foods because they think it is better for their coat but that may not be so. It used to be more dogs were allergic to proteins in the standard dog foods, than to the proteins in Lamb and Rice foods. The standard foods previously had chicken and beef as the primary source of protein. Soy and corn were the primary carbohydrates. But these carbohydrate sources both have relatively high levels of protein. So, it makes sense to feed dogs Lamb and Rice, right? Well, yes and no. Most dogs will do well on it. However, most of these dogs have also been given regular treats that contain the other more common proteins. If these dogs had a tendency to food allergy, and then were fed these other proteins in addition to Lamb, they would more readily develop a sensitivity to the lamb also. So, the lamb and rice food was good, but the diet should have been controlled to limit the protein ingestion to lamb only. Which, this is hard to do. We all like to give our pets treats. Additionally, some foods are labeled as Lamb and Rice', but read the ingredients; they still contained other protein sources.

So, how do we determine if our pets have a food allergy? We use a food with the protein that has been processed to prevent an allergic reaction. Additionally, this food does not have preservatives. This food and nothing else is to be fed for 8-12 weeks. If after 12 weeks, there is no improvement, then we have ruled out food allergy. On the other hand, if there is complete improvement, then the allergies are mostly food. If we have improvement, but not complete, we suspect a combination of inhalant and food allergy.

If we determine that food allergy is involved, we can continue on this special diet, or we can start to test individual food substances, in order to determine which other foods the pet can handle. We can add in a new substance every 1-2 weeks. If there are no detrimental effects, that food is okay to continue to be fed. A warning, though, when a substance is found that the pet is allergic to, the effects can be drastic. The skin can suffer, but there may be a strong gastrointestinal upset. After all, the GI tract is really just specialized skin.

Many times instead of doing the above food trial, we will start dogs on a food formulated for its limited antigen and very high fatty acid (omega 3) in it.  It is a Salmon and Rice veterinary formula made by Purina called LA.  This is a food that has helped so many dogs in my practice and is the food I feed my own dog.  A brochure is available.

 

Contact allergies were not thought to be common in our pets but now we are realizing that atopic dogs are also sensitive to allergens on their skin. Chances are, if there is a substance that could irritate your skin, it can irritate your pet's skin. Many times, we see more irritation or coat changes due to intolerance to a shampoo or conditioner we have tried on our pets. Additionally, if these substances are not properly and fully rinsed off, they may initiate dermatitis. In general, if you use a product, and the pet is not more comfortable after using it, do not use it again.

Another form of contact allergy is staph dermatitis'. We all have bacteria on our skin. The skin is meant to keep bacteria out of our bodies. However, if the skin is compromised, as with allergic skin disease, certain bacteria have a habit or ability to enter the deeper layers of the skin and cause eruptions that we call pustules. When these break open, they leave a temporary ring of flakes and redness. The pustules are puritic (itchy) so they are usually broken open once they begin developing due to our pets scratching and chewing at themselves. We need to use antibiotics to help the skin control the bacteria until the skin is once again healthy enough to keep the bacteria out as it was meant to be.

Secondary yeast infections are common with dermatitis. Similar to secondary bacterial invasion, a yeast invasion can cause puritis, and much smell.

 

Testing

 

We need to determine if the pet is compromised in any other way. 

Thyroid and general blood profiles are used to determine if there is underlying or other chronic disease conditions. Since skin disease is worse in face of hypothyroidism or other chronic diseases, we cannot form a complete treatment plan without completing a laboratory panel.

Blood Allergy testing is the typical way we detect allergens in atopic dogs.

A Skin Scrapping is used to determine that there are no parasites involved other than fleas.  There are some mites that are difficult to detect even with deep skin scrapings.

Bacterial Culture and Sensitivity can be used to determine what bacteria are involved, as well as which antibiotic(s) the bacteria are sensitive to.

A fungal Culture can be completed to rule out fungal diseases.

Skin biopsy will be completed in cases that are unusual or not responding to treatment.

 

Treatments

 

Treatment for skin disease is multifold. A combination of medications and recommendations will be made. These will be based on the severity of the disease seen in the pet during examination. The treatment routine can be modified as time goes by, and seasons change. Not every dog with an itch needs medications. We will try to guide you in treating your pet, without over treating.

 

Antihistamines are used to help stop the itch, help the pet be more comfortable, and reduce self-trauma. There are several antihistamines that we use; some pets will need a combination of two products to achieve the comfort we want them to have. Antihistamines have relatively few side effects and can be used on a long-term basis. The greatest or most common side effect is drowsiness. We can adjust the dose, or the medicine to reduce the drowsiness if this is perceived as a problem.

 

Antibiotics are required when the skin has a bacterial infection. Many times, with skin disease, it may take 6 or more weeks to rid the skin of the infection. On occasion, particularly if we cannot identify the cause and provide relief, some pets may need pulse' antibiotics. Use antibiotics only as prescribed and until they are gone. Proper use of antibiotics is important to reduce the incidence of bacterial resistance to these medications. Bacterial culture and antibiotic sensitivity testing will be completed if infection is recurrent or severe.

 

Antifingal medications may be prescribed in refractory cases with secondary yeast infections. Most pets that are otherwise healthy should be able to rid themselves of a secondary yeast infection without antifungal medication. Antifungal medications tend to have greater number of side effects, and are used only if no other alternative is available.  Pets on antifungal medications will need blood profiles completed regularly to determine if prescriptions can be renewed.

 

Fatty Acid supplement should be started on all pets with dermatitis. Many pets require higher levels of these nutrients than are in our standard pet foods. Among other functions fatty acids help prevent the reaction in the skin that leads to redness and puritis. (One of the other great functions for fatty acids is in arthritic disease). Fatty acids may be added to the diet by capsules, commonly given as a treat, or by a pour over food form. Most pets enjoy these supplements.  We offer both a liquid that can be dropped onto the regular diet, or a capsule that most dogs will accept as treats once they are familiar with them. We have found Salmon oil to be especially high in omega 3 fatty acids and is very useful for pets with dermatitis.  Fish oil capsules are helpful but tend to be the oil from the liver of the fish and does not have the same ratio of omega 3 to omega 6 fatty acids and seems to not have as much benefit as other products.

 

Prozyme

File NameDescription / Comment
Hyposensitization information from VARL