Allergies

Looking After
Your Pets Health

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Geneva, IL

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Allergies

Allergies in dogs are a very common problem. Unlike people that develop sneezing and sniffling with allergies, most dogs develop itchy skin. This is potentially related to where histamine and other inflammatory substances are released within the body in response to an allergen (a substance that results in an allergic response). The degree of signs will vary with each patient. Not all patients are allergic to the same substances. Likewise, not all allergens are located in all geographical areas, so a patient may do well in one area, but upon moving may become allergic. The majority of allergens are dusts, pollens, wool, etc. The most common allergy in pets though, is to fleas, (the allergy is actually to the saliva from the flea bite). This makes flea control imperative in any allergy patient. Inhaled allergens are the next most important cause of allergies, (referred to as atopy) then food allergies. Patients with allergies are also more prone to secondary skin infections, (pyoderma) and to ear infections (otitis). Below is more information and things to consider in your pet:

Diagnostics

History

When did your pet first develop itchiness?

Dogs less than 1 year of age may be more likely to have mites, food allergies or other causes of itchiness

Did itching develop after moving?

What time of year is your pet itchy?

A pet that is only itchy in the spring, summer or fall may only be itchy outdoor pollens, while a pet that is itchy in the winter or year-round may have more indoor allergens, multiple allergens or have food allergies.

Do other pets in the house itch or do you itch?

If you and other pets are itchy, scabies and ringworm must be ruled out

If just the pets are itchy, make sure fleas are not the problem, this is the #1

cause of allergies in dogs and cats

Physical Exam

A thorough physical exam is an important diagnostic tool for ruling in or out certain conditions

Is the skin oily?

Is there crusting or severe seborrhea?

Are there pustules or papules?

What body areas are affected?

Is self-trauma evident?

Are the ear tips and distal limbs worse than other parts of the body?

Any moving mites, fleas ticks or other parasites found?

Cytology

A sample of the crusts and oil on the skin is examined under the microscope to look for bacteria or yeast that can complicate allergic pets.

Skin scrape

This helps to rule out scabies, this mite is difficult to find and may

warrant empirical treatment with revolution or ivomec.

Response to therapy

Response to antibiotics or cortico-steroids can help diagnose atopy. The majority of pets with allergies will respond very well to cortico-steroids.

Skin biopsy

Confirms an allergic type reaction

Rule-out other disease like pemphigus

Does not diagnose what pollen, mold etc the pet is allergic to

Strongly recommended in cases that do not respond to traditional therapy.

Allergy testing

Determine what allergen is affecting the pet

Not all allergens can be tested for

If an allergen is found, a serum is given by injection on a routine interval (usually

weekly)

Between 65% to 75% success rate (this figure varies)

Are not effective for determining food allergies

The patient should be off all medications prior to testing, preferably

Generally wait until the patient is 1 year old to get exposure to a full season of

allergies

Types of Allergy Testing

Blood tests (RAST or ELISA)

A blood sample is sent to a laboratory to screen for antibody (IgE) to specific

allergens

Simple, can be ran by any hospital

Results may not correlate quite as well as IDST

Intradermal skin testing (IDST)

Samples of allergens are injected in a grid pattern just into the skin on a

patient

Exaggerated response indicates an allergy to a specific allergen

Usually performed upon referral to a specialist

Much discussion ongoing about value versus blood tests

Usually more expensive

Sometimes a combination of the two may be required in difficult cases

Dietary trial

Must be with a food the pet has not been exposed to or a low molecular size

diet

Home cooked diets are preferable, but often difficult for many owners to

perform

Many diets are available, but no single one may be the correct in a given patient

Give only the exclusion diet, absolutely nothing else (NO Treats)

Must give at least 8-12 weeks to have a positive effect

Therapy

Corticosteroids

Very effective for most atopic allergies

Effective treatment for the patient that is only itchy for a few weeks or so each year

Side effects if used chronically at high dosages

Increased drinking and urination

Iatrogenic Cushing’s

Thinning of the skin

Liver disease

Predispose to secondary infections

Muscle loss

Not as effective for food allergies

May not be as effective after long-term use

Not recommended for long-term use

Allergy serum injections (Immuno-therapy)

Determined based on blood tests or skin testing

Recommended for pet with chronic allergies

Injections of dilute amounts of allergen are given to “modulate” the pets immune system.

This is the only method that does not involve immuno-suppression

May take 6 to 9 months to see a dramatic response

Very individualistic treatment, (dosage, frequency, etc)

About 65 to 75% of patients respond well

Many patients may still need adjunctive therapy during high allergen seasons

Very well tolerate, although reactions are rare they can occur

Atopica

Antirejection medication used to decrease the immune response

Well tolerated, but some pets can vomit

Adjunct therapy

Omega 3 fatty acids

Omega 3 fatty acids may result in inflammatory mediators

Help to regulate replication of the epithelial cells

Help maintain moisture in the skin and follicles, preventing dry skin

May be more beneficial when used in combination with other therapy

Antihistamines

Many available, many different responses

Effective for mild cases in some patients (maybe 30%)

May help reduce the dosage of other medications (corticosteroids)

Few side effects

Bathing/Medicated shampoos

Delivers medication locally, less chance of systemic side effects

Help reduce allergen on the patient

Control bacterial and yeast overgrowth

Soothes the skin

Help control oily or dry skin

Allergies can be a frustrating and difficult condition to control. There is no “Silver Bullet”, so set realistic goals. Pets will not be cured of this condition, only controlled! While everyone would like their allergic pet to itch no more than a normal dog, flare-ups are going to occur. This is no different than an asthmatic person. Therapy will be designed to keep your pet as comfortable as possible. No single therapy is effective in every patient.

Canine Atopic Dermatitis

Diagnostic Checklist

□ Age at onset <3

□ Mostly indoor

□ Corticosteroid-responsive pruritis

□ Chronic/recurrent yeast infections

□ Affected front feet

□ Affected ear pinna

□ Non-affected ear margins

□ Non-affected dorso-lumbar area

This validated checklist is 85% sensitive and 79% specific when dogs meet at least 5 of the 8 criteria.* It is important to invstigate and rule out alternative or concurrent diagnoses based on the clinical findings.

*FavrotC., etal Vet Dermatology 2010