An allergy is a state of hypersensitivity in which exposure to a 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.

Pets more commonly they experience the effects of allergic hypersensitivities as skin problems. This can often be seen as redness and scratching, recurring skin or ear infections, and hair loss. Persistent scratching and chewing can cause massive discomfort, distress and affect your animal’s quality of life.

FLEA BITE HYPERSENSITIVITY

Fleas are both a leading cause of self-mutilation, especially centred on the tail base, and are the most common trigger of skin allergies. These days there are excellent, safe products to eliminate them but beware of buying flea and tick products from questionable sources. Some products sold over-the-counter are not effective and some can actually be harmful to your dogs and cats. Your veterinarian is an ally in getting the correct, effective and safe treatment.

For the flea allergic patient, 100% flea control is essential for the pet to remain symptom-free.  As veterinarians, we commonly hear “But I never see fleas on my pet.” Remember, you may not see them, but that doesn't mean they're not there, as adult fleas spend 90% of their time off your pet, in the surrounding environment. In-fact in Flea Allergy Dermatitis studies, 50% of all animals suffering with this condition present with no fleas visible on their skin surface! This allergy is actually caused by over reaction to the flea's saliva, injected into the skin surface and it only takes a few bites to induce a massive problem.  Remember also that in the warm indoor climates of our homes, fleas survive at least in low numbers all year-round. Since flea allergy dermatitis is so common, we recommend that complete year round flea control be instituted before proceeding with diagnostics for other allergies and that it also be maintained for all other allergy patients as the presence of any flea saliva will make any other allergic conditions much, much worse.

DIETARY ALLERGY

Some pets develop specific hypersensitivities to components of their diets. This can

happen even if the pet has been on the same diet for many years. It is this point that often trips up owners when trying to deduce possible causes for themselves. The offending component doesn’t have to be a new food item!  People and pets can become allergic to something they have had in their diet for months or years; many common allergies require multiple exposures over a period of time before reaching a threshold to trigger an inappropriate inflammatory response. The allergen usually is a major protein or carbohydrate ingredient such as beef, chicken, corn or wheat. Minor ingredients such as artificial preservatives or dyes are also potential allergens.

If we suspect a food allergy we will recommend feeding special diets that contain only ingredients that the pet has never or hardly ever eaten before (and is therefore not likely to be the culprit) e.g. Tapioca and white fish based food. The special diets we can select from also have hydrolysed proteins. These are protein chains which have been broken down into very small pieces. These segments are too small for IgE receptors on the surface of allergic “Mast” cells to bind to. This cleverly prevents the inappropriate allergic response, halting the release of harmful histamines from these cells.

When we are suspicious of a dietary cause of skin disease in a pet we institute a dietary trial for a minimum of 6 weeks and observe the skin for a response. We strongly encourage the pet’s owner to follow these guidelines during that 6 week period to allow us to get a definitive answer.

• Feed your pet only the prescribed diet. No other foods or treats are allowed.

• Make sure all family members know that your pet is receiving a special diet.

• If you need to use rewards or training purposes, use some of the prescribed diet.

• If you have other pets feed them the same diet or feed them separately.

• Keep your pet away from the diner table during meals

• If pills are prescribed don’t hide them in anything other than the prescribed diet.

• If your pet tries to eat rubbish scraps when exercised outside, keep it on a leash.

ATOPIC DERMATITIS

Inhalant allergies are very common. Although people usually have respiratory symptoms with inhalant allergy, dogs usually have problems with their skin and ears. Common inhaled allergens include pollen, grass, dust mites, mould, all though it can be from any other airborne particles.

Inhalant allergies in dogs usually cause scratching, chewing, or licking of the paws, limbs and abdomen, and rubbing around the eyes causing hair loss and reddening and thickening of the skin. Inhalant allergies in cats usually cause itching of the face and the eruption of small skin scabs over their head and torso.

These symptoms often initially occur seasonally in spring-summer, but can then develop into a year-round problem. They commonly begin when the pet is from 1 to 3 years old. Diagnosis of inhalant allergy is made based on the results of intra-dermal skin testing, similar to patch skin prick testing in people.

Because of a strong hereditary component to this disease, several canine breeds, including Retrievers, Terriers, Setters, Lhasa Apsos, Dalmatians, Bulldogs, Beagles, Schnauzers, Pugs, Boxers, Spaniels, and Shar Peis are more commonly affected by atopy.

SECONDARY INFECTIONS

Skin allergies are also the most common underlying cause of recurring skin and/or ear infections. While bacterial and/or yeast infections can be primary causes of itching, most often they are secondary, taking an opportunity to invade and multiple in already inflamed, altered skin. Because of this long-term treatment with antibiotics and anti-yeast medications is commonly required along with routine medicated shampoo washes.

TREATMENTS

Atopy treatments falls into three broad categories: Drugs to remove the itching sensation and reduce inflammation, identifying and subsequent avoidance of exposure to allergens, and the use of “vaccines” to desensitize the animal and reduce the inflammatory response.

DRUGS

Antihistamines can decrease the itching sensation in about 10% to 20% of atopic pets. Your pet can be on antihistamines with no serious long-term problems. The only side effect sometimes seen with antihistamines is drowsiness. Several different types of antihistamines may need to be tried to find the one that works the best. These have a slow onset of effect and should be given for a few months before a decision is made concerning their effectiveness. In realistic terms, anti-histamine usage is often disappointing and only seems to be effective in a few animals, and often these are only those animals with mild signs.

Corticosteroids can also be used to alleviate the itching. These drugs are excellent at controlling the clinical signs; however, they do have potential side effects and are ideally reserved for pets for where other therapy is not possible, therapy is ineffective or to control a severe itch for a short period of time.

Cyclosporin (Atopica™) is a relatively new drug which is often highly effective at controlling the symptoms of atopy. It works by reducing the inflammatory response of the skin. The drug is generally safer for long term use than steroids, but is currently very expensive, especially in large pets a sits dosage is determined by body weight.

Products applied topically to the skin (shampoos, conditioners, gels, lotions, sprays) with anti-itch properties may also be of benefit. These products will usually need to be applied daily or a few times weekly.

Essential Fatty Acid supplements (or the choice of diets rich in these) such as flax seed or fish oils help the body to regulate inflammation and will reduce long term the amount of drugs required for treatment.

AVOIDANCE

Avoidance can be difficult as you may not be able to easily identify the trigger allergens that your pet may be allergic to. However it is known that certain common allergens frequently have a role to play, and although complete avoidance of the allergic substance may not be practical, decreased exposure may be feasible.

POLLEN: Decreasing the outdoor exposure especially at dusk and dawn is helpful. Your pet should never be walked through fields with high grass or weeds and should not be outside when the lawn is cut.

FUNGI/MOLD: You pet should not be kept in rooms with high moisture levels (bathroom or laundry room) or allowed to be in areas of increased dust. Homes with heat-pumps minimise this.

HOUSE DUST MITES: Avoidance may be a major undertaking, involving the removal of carpeting, covering mattresses, regular washing of the bedding, high-efficiency vacuuming, avoiding stuffed toys, and frequent damp mopping of the areas most frequented by your pet.

DESENSITIZATION VACCINES

Desensitization vaccines can be formulated for your pet on the basis of results of a skin test. After an initial series of injections, periodic boosters are needed (every few weeks) for the remainder of your pets’ life. Over 50% of animals show some improvement with such vaccines over a period of many months of treatment. In reality – it is felt that there is quite a varied response, a big undertaking and is expensive.

Skin allergies require a lot of patience, sound deduction and long term management to get on top of what can be some very debilitating symptoms. There are many treatment options to combine with environmental or dietary modifications.

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