Annabessacook Veterinary Clinic
417 Route 135
Monmouth, Maine 04259
Itching and Allergy in Dogs

Coping with an itchy pet can be an extremely frustrating experience for you, the pet owner, and can truly test the limits of the human-animal bond. Persistent scratching and chewing by the pet can also result in self-trauma and open wounds. The following information is intended to provide the pet owner with a basic understanding of the most common underlying causes of itching and allergies in small animals.

The Most Common Causes of Chronic Itching
The common causes fall into two groups: external parasites and allergies. External parasites that most commonly cause chronic itching dermatitis include fleas and sarcoptic mange. We often recommend therapeutic trials for sarcoptic mange in chronically and severely itchy dogs. We always recommend stepped-up flea control and monitoring for fleas, as flea infestation can really make allergy worse!

What are Allergies?
Allergy is a state of hypersensitivity in which exposure to a harmless substance known as an allergen induces the body’s immune system to “overreact.” The incidence of allergies is increasing in both humans and their pets. People with allergies usually have “hay fever” (watery eyes, runny nose and sneezing) or asthma. While dogs can rarely also have respiratory allergies, more commonly they experience the effects of allergic hypersensitivities as skin problems. Though there are a variety of presentations, this can often be seen as redness and itching, recurring skin or ear infections, and hair loss. This is sometimes called atopic dermatitis.

What are the Major Types of Allergies in Dogs?

Flea Allergy
Flea allergic dermatitis is the most common skin disease in dogs and cats. For the flea allergic patient, 100% flea control is essential for the pet to remain symptom-free.
“But doctor, I never see fleas on my pet.” You may not see them, but that doesn’t mean they aren’t there. The allergy is caused by the flea’s saliva, and it only takes a few bites to induce the problem. Also, the itchy pet often scratches so much that adult fleas are removed, making them hard to find.
“If fleas are the problem, why is my pet still itchy in the winter?” In warm climates or in our homes, fleas may survive in low numbers year-round. Because flea allergy is so common, we recommend that complete flea control be instituted before proceeding with diagnostics for other allergies and that year-round flea control be maintained for all allergy patients.

Food Allergy
Some pets develop specific hypersensitivities to components of their diets. The allergen usually is a major protein or carbohydrate ingredient such as beef, chicken, pork, corn, wheat, or soy. Minor ingredients such as preservatives or dyes are also potential allergens. The diagnosis of food allergy requires that we test your pet by feeding special strict diets that contain only ingredients that he has never eaten before. This is often achieved by feeding a prescription diet for a period of 10 to 16 weeks. If the signs resolve, a challenge is performed by feeding the former diet and watching for a return of the itching. If this occurs, a diagnosis of food allergy is confirmed. Only about 1 in 4 dogs has a food allergy.

Atopic Dermatitis
Atopic dermatitis (AD) is an inherited predisposition to develop skin problems from exposure to variety of commonplace and otherwise harmless substances including the pollens of weeds, grasses and trees, as well as house dust mites and mold spores. Diagnosis of AD is made based on the results of intradermal skin testing or by in vitro blood testing. Evaluating the results of these tests helps us compile a list of allergens for a “vaccine” to decrease the pet’s sensitivity. Sometimes multiple skin and/or blood tests are necessary to accurately assess the patient’s allergies.

Secondary Infections
Allergies are often the underlying cause of recurring skin and/or ear infections. Bacterial and yeast infections, though secondary to the allergy, can cause an increase in your pet’s level of itching. Long-term treatment with antibiotics and anti-yeast medications is commonly required, along with medicated bathing programs.

Can Allergies be Cured?
Unfortunately, there is no cure for allergy and it is usually a life-long problem. We seek to control allergies and improve the quality of life for both you and your pet. We will formulate the best program of management that suits all involved with your pet’s care.

Treatment of itching and allergies often includes several types of therapy including the use of flea preventatives, antibiotics, antihistamines, dietary supplements, bathing and other topical therapy. In severe cases, steroids may be used to help break the “itch cycle” and allow relief while other medications begin to work.

1) Antihistamines: The protocol recommended by this hospital is helpful to approximately 40% of dogs who try it. Four different antihistamines are used, one at a time, for at least 2 weeks each - in hope of finding one that is acceptably effective. While the chance that an individual antihistamine will be helpful is small, trying several antihistamines greatly increases the chance of finding one that works. If antihistamines work for your pet, antihistamines can be taken for life. The only side effect usually seen is drowsiness. Several types may be tried to find the one best for your pet.

2) Avoidance of the allergens: This can be helpful for house dust mite allergies. Pollen exposure can be reduced by using air-conditioning and air filters, avoiding the outside early morning and late afternoon, wiping down with moist cloths after going outside and frequent bathing.

3) Fatty acid supplements: Certain types of oils can reduce allergic symptoms in some patients. We can give fish oil capsules diet or prescribe special prescription diets with the fish oil content raised. This therapy can help improve response to antihistamine therapy. Fish oils can be obtained at many establishments; however, we stock supplements that are specially-formulated for dogs and cats. These products contain guarantee amounts of fatty acids as well as vitamins that may help improve your pet’s symptoms.

4) Bathing: Allergic skin is sensitive and subject to drying. Only specially designed hypoallergenic shampoos should be used on your allergic dog. Rinsing should be thorough. There are many choices for shampoos including over the counter varieties and medicated shampoos. Your doctor will help you decide which product is right for your pet.

5) Oral Steroids (prednisone, cortisone, triamcinolone, etc.): These drugs have many potential side effects and are reserved for adult animals, those with short seasonal problems or where other therapy is not possible or is ineffective. Typically, treatment is started at one dose and then tapered off to every other day usage. Potential side effects of these medications including increased thirst and urination as well as increased appetite and panting.

6) Antibiotics: Antibiotics may be prescribed if your pet has a skin infection that resulting from scratching or chewing at his/her skin. It is vitally important that we treat skin infections before attempting to alleviate symptoms associated with allergies because the inflammation caused by the infection can often exacerbate many of the problems associated with allergies.

It is important to remember that allergies have many components and thus, diagnosis and treatment can be challenging. Symptomatic therapy is often tried initially, but many patients’ symptoms are not completely controlled year-round without some adjustments. It is important that you follow instructions carefully and discuss therapy with your doctor regularly in order to tailor medications to suit your pet’s specific needs. If symptomatic therapy is not completely successful in your pet, your doctor may recommend a food trial to help diagnose food allergies and/or allergy testing to help better determine the underlying causes of your pet’s signs.

Instructions For Your Pet

Topical Therapy:
A. Locally _________________________________________________________
B. Whole body _________________________________________________________

Bathing Protocol:
Bath at least once a week with _________________.
Lather 10 minutes, rinse very well.
Follow with a spray or cream rinse (_______________) to rehydrate as indicated.

Systemic Therapy:
□ A. - Steroid therapy:
Give ____ mg once a day for _____ days,
then ______ mg once a day for ________,
then _______ mg every other day for _______days.
□ B. - Antihistamine therapy:
Give ______________, _____ mg once ____ or twice ____ a day, indefinitely.
□ C. - Fatty Acid Therapy:
Give ______ capsules, daily with food or use _________ prescription diet.
□ D. – Antibiotics:
Give ______________, _____ mg once ____ or twice ____ a day