Skin Allergies

Skin allergies are very common in dogs.

Atopy

Atopy is like hay fever in dogs.  It is an allergy to environmental allergens (eg dust mites, pollens etc) that may be seasonal (eg pollens in Spring) or non-seasonal (eg dust mites).  Dogs may be allergic to a number of different things, which can cause non-seasonal allergies to have severe flare ups at certain times of the year (eg a dust mite AND pollen allergy will be present all the time, but worsen in Spring).  Dogs most commonly become affected by atopy when they are 6 months to 3 years of age, but it can develop at any stage of life.

Food allergies

Dogs can also be allergic to certain foods.  The most common food allergies in pets is to an animal protein (eg chicken, beef, lamb, pork etc).  In the case of food allergies, they are non-seasonal (occur all year round), and are most commonly associated with a stable diet, rather than a change in diet. 

The features of atopy and food allergies are indistinguishable, a food elimination trial is required to distinguish between the two.  Dogs are generally itchy, especially licking the feet, around the face and ears, and they often get ear infections.  They have a variable response to antihistamine therapy and often get secondary bacterial and yeast infections that make the itch worse and require specific treatment.

Food elimination trial

A food eliminiation trial is required to distinguish between a food allergy and atopy.  We need to feed a diet that contains a novel protein source (i.e. a protein that the pet has never had before, often kangaroo is a good choice as it is readily available and most pets will not have been exposed to this) and a carbohydrate (cooked rice or sweet potato, other veges).  There are also commercial diets prepared for this exact reason, we use Royal Canin Anallergenic (we can order this in for you, but we do not stock it so make sure you let us know before you run out!!).  This diet needs to be fed exclusively for 8 weeks.  No treats, no flavoured worming chews, no chewing on a dead bird or someone’s burger rubbish when walking!! There may be medications at the beginning of the food trial to help with any secondary infections or anti-inflammatories to control a really bad flare up.  If we get to the end of the 8 weeks and there has been an improvement while on the new diet, we then need to re-challenge with different proteins.  Feed beef for 2 weeks, then chicken for 2 weeks etc etc.  A diagnosis of food allergy relies on a relapse of the signs with introduction of the food.

Food allergies are not nearly as common as atopy.  But if we do happen to have a dog allergic to a protein, we are able to avoid it completely and we then have a complete resolution of the allergies for life!  It is worth the 8 weeks of food trial just in case!!

Medical management of atopy:

Medical management of atopy is ongoing and often frustrating.  We need to treat firstly the secondary infections, and from there we must manage the underlying allergy.  Some dogs will need medication only intermittently, and others will need it year round.  With medical management we do not expect to get full resolution of allergies, we do expect to get flare ups, often at a particular time of year.

There are a number of areas to approach when considering a multi-faceted approach to your dog’s atopy:

1 – Prevention of bacterial and yeast infections:  This is very important in patients that often suffer from secondary infections.  We use antimicrobial shampoos (eg pyohex, malaseb), solutions and creams (eg neocort).

2 – Barrier repair treatment: The skin’s barrier is damaged in pets with atopy, and this is the part of the body that is letting the allergen in.  Repairing the barrier means less particles enter the skin to cause a reaction. 

-          Fish oils (1000g capsule / 10kg bodyweight daily)  AND evening primrose oil (also 1000g / 10kg bodyweight daily).  Need both to get omega 3 & 6.  Caution weight gain!

-          Shampoos – maximum twice weekly for severely affected dogs, can alternate medicated and soothing shampoos.  Eg malaseb or pyohex alternated with aloveen or nutriderm.  Ensure to condition the hair and skin afterwards (dry skin is itchy and this helps to repair the barrier surface!!)

-          Lotions and oils – can use intermittently (eg twice weekly) to soothe and repair the skin.  Eg alpha keri, QV, dermaveen.  Can use the lotion, oil or cream of all of these products.

3 – Mild anti-inflammatories: This is important in a long term treatment plan.  Antihistamines are mainly used here, see additional handout for antihistamines used in dogs and their doses.  We also have a new drug called Apoquel that has shown great results when used long term for allergic dogs.  There are also strong topical steroids (Cortavance spray) that can be useful to spray onto affected skin in acute flare ups.

4 – Strong anti-inflammatories:  This is important for poorly controlled allergies.  Steroids and other immune suppressants are sometimes necessary for acute flare ups (used short term) and part of a long term management.  We need to keep in close communication when using these for short and long term use.

5 – Avoid any flare factors: Fleas make dogs itch!  We do not need anything else to make an allergic dog even more itchy!  A high level of flea control for all animals in the house is a must!!  Please have a chat with us as to what flea treatments are appropriate for allergic dogs (especially if your dog is currently on a food trial!!).

6 – Immunotherapy (allergy vaccines) – see below.

Skin testing and allergy vaccines:

For the majority of allergic dogs that aren’t lucky enough to have responded to a food trial, there is more we can do.  A dermatology referral (to Sydney) is available, where skin testing is carried out.  Approximately 50 allergens are injected under the skin on the side of the dog and the skin reaction is measured to determine exactly what the dog is allergic to.  Allergy vaccines specific to your dog’s allergies can then be made and administered every couple of weeks (one injection every 3 weeks is the maintenance dose) over the next 2+ years. 

The response to allergy vaccines is variable.  Some dogs will have an excellent response to the vaccines, where no treatment is ever required (20-30%).  Most dogs will have a partial response, where the medication required is much reduced and the severity of flare ups is reduced (40-60%), and some dogs will have no response at all to the vaccines (20-30%).  The initial cost for consultation and skin testing, plus allergy vaccines for 12 months is around $1500, and you would be expected to pay around another $500-1000 for the remainder of the treatment (total treatment cost $2500-3000).

For any questions please do not hesitate to contact us on 02 6884 9900