Atopy / Environmental Allergies

 

Allergies - Atopic Dermatitis

As with people, allergies are as common in our beloved pets as they are in people.  Humans tend to have inhaled allergies where people breathe in pollen, mould or dust which cause an allergic reaction of coughing and sneezing.  Dogs differ in that they get contact allergy where the same mould, dust or pollen contact their skin and cause itching and licking.  This is an unpredictable disease and there has been shown a genetic link, but unfortunately there is no test  to tell if the pet you are bringing into your family will have atopy or not.

Atopy is the most common health condition we see in veterinary medicine.  The good news about this is that it means we have developed many tools and medications to help your pet live with this ongoing condition.  There is NO CURE for allergies and we can only MANAGE THIS ONGOING DISEASE.

Any breed of dog can develop atopy.  Especially in climates like Queensland, dogs can have varying allergy flare ups.  Some dogs will have 1 flare up per year where others will have continuous flare ups and need to be on medications all year long.

There are many reasons for pets to itch: parasites, allergy to flea bites, food allergies, secondary infections and the list goes on.  The most common being environmental atopy.

 

Other allergies other than environmental

  1. Fleas allergies are generally noted with dogs or cats scratching around the base of the tail. You can often but not always see evidence of fleas.
  2. Food allergies - These pets often have hair loss around their face and anus.  They often scoot their bottom along the ground, have continually itchy ears, and often have intermittent appetites, vomiting and diarrhoea.  Food allergies are not often diagnosed as the primary allergy and generally these dogs also have environmental allergies.

 

Diagnosis

Some clues as to whether your dog may have ongoing issues are:

  1. Age of onset - Seasonal itchiness due to atopy tends to begin early in a pet's life although some dogs will develop this in later life
  2. Mostly indoor lifestyle - It is indoors where many airborne allergens are concentrated; however, it is important to note that allergens in the air are in the air for miles so it is not easy to escape allergens by simply going outdoors nor by simply going indoors.
  3. Good response to steroids - Whether the patient is a dog or cat, itchiness due to atopy responds rapidly to cortisone-type medications (prednisone)
  4. Chronic or recurring yeast infections in the skin - Yeast (Malassezia pachydermatis) lives on the surface of the skin normally but with all the changes allergies cause to the skin's micro-environment, yeast will proliferate and create a stinky, thickened, pigmented skin.
  5. Front feet involvement - Whether it is chewing the top of the feet or between the toes, foot licking is a classic feature of atopic dermatitis.
  6. Seasonality - seasonality of the itching is also a clue towards an airborne-related allergy, but since there are many climates where seasons are ambiguous, this is not necessarily a hard and fast feature of atopic dermatitis.

 

 


There is no Test for Atopic Dermatitis

Unlike other diseases where a test of some sort can be performed, atopic diagnosis is a clinical diagnosis, which means the diagnosis is made based on symptoms and findings such as those listed above.


Treatment Options

Many patients will not be particularly itchy in between infection flare-ups so treatment depends on the severity of each dog's allergy. 

First, secondary infections need to be cleared. Before doing anything else, it is important to clear up any secondary infections. Secondary infections involve bacteria (usually Staphylococcal) and/or yeast (Malassezia) at the site of the itchiest areas on the body. These organisms live naturally in the skin but when the skin is irritated, they gain access to inner tissue layers and proliferate. Sometimes they actually come to increase the allergic response in the skin. These infections tend to recur and are the usual cause of recurrence of itch symptoms in a patient who was previously controlled.

 

Medications to Control Atopy

  • Steroid Hormones - These cortisone-type medications (prednisone) tend to be useful as the first line of defence against itchy skin. A higher dose is used at first but this is quickly tapered down once the condition is controlled. An atopic pet will usually respond within days. The benefits of this medication are that it is inexpensive, works well and works quickly. The side effects are many and include: excess thirst, excess hunger or excess urination which could lead to house-breaking issues. Suppression of the immune-system can bring out a latent infection, especially urinary tract infections and upper respiratory infections. The best way to describe side effects from these medications is that it causes the body to age fast, so if used often it will shorten a pet's life span.  Steroid hormones are useful for acute flare-ups as well as for long-term management if there are financial limitations.
  • Oclacitinib (Apoquel) - This is a new medication best used for itch relief and blocking itch symptoms. It is popular as it works fast. It does not address the inflammation in the skin; it just stops the itch sensation.  There are very few side effects with this medication and it works wonderfully in approximately 70% of cases.  Its down fall is that it is a once a day tablet that must be administered daily and is expensive compare to Steroids.
  • Canine Atopic Dermatitis Immunotherapeutic (Cytopoint) Injections – This is our BEST CHOICE and is our PREFERRED TREATMENT OPTION - This is a relatively new treatment that uses advanced vaccine technology to eliminate one of the main mediators of itch sensation.  Cytopoint is given as an injection by your veterinarian and lasts 4-8 weeks. It is amazingly safe, effective in over 90% of dogs, works quickly and has revolutionised the treatment of atopy in dogs. We strongly recommend this for our allergy dogs!  This option is more expensive that treating with steroids, but is vastly superior and has relatively zero side effects.  It is also more affordable than above mentioned Apoquel.
  • Hyposensitisation (Allergen Specific Immunotherapy) - Hyposensitisation, is another option for managing atopy.  Referral to a veterinary dermatologist may be necessary.
    • Allergy shots require approximately 6 to 12 months to begin working.
    • 25% of atopic dogs will not respond (these are usually the animals allergic to multiple allergens).
    • 25% will require prednisone or similar steroid at least at some times.
    • You will most likely have to give the allergy shots yourself.
    • In hyposensitisation, the patient is injected with small amounts of allergens on a regular basis. As time passes, the amounts of allergens increase and injections are given at longer intervals. The selection of allergens is made based on the results of either an intradermal skin test (as described above), an in vitro test (a blood test) or a combination of the results of both tests. The younger the pet is when this treatment starts, the better it works.

Other Helpful Options to Consider

  • Regular bathing using medicated shampoos
  • Regular grooming - keeping hair short and clean
  • Regular quality flea prevention - such as bravecto or nexgard