Seasonal Allergies Part 1: Atopy, Etiology and Pathogenesis
Atopy Atopic dermatitis (AD) is a genetically predisposed, inherited, inflammatory, and itchy skin disease with characteristic clinical...
Most symptoms of environmental allergies in dogs are associated with dermatologic problems. Sometimes an owner will bring their dog to a veterinary appointment, suspecting a serious medical condition and end up finding out that their canine companion has an allergy.
SIGNS & SYMPTOMS
Excessive licking of the paws, armpits, groin, perineal area & belly
Regularly rubbing face & body against the ground, walls, furniture, etc.
Red skin, scabs, pimples, and scales
Bad body odor (seborrheic odor)
Red, swollen, or painful ears
Dark or tan discharge from ears
Runny & red eyes
Vomiting and/or intermittent soft stools
Frequent sneezing and/or wheezing
COMMON SKIN CONDITIONS
Through a thorough exam & appropriate testing, Dr. Limpach will determine the underlying cause of your dog’s symptoms. Dog allergens fall into the following groups:
Environmental allergy - including many kinds of grasses, plants, dust mites and molds
Flea allergies - many dogs are highly allergic to flea bites
Food allergies/adverse food reactions - offending items can be anything your dog has eaten during his lifetime
Inhalent allergy (Atopy) - allergens that are inhaled
* Environmental allergies are by far the most common. These cause severe irritation to the skin, causing your dog to scratch to the point that infections and injuries occur.
2 TYPES OF TESTING
Blood Testing & Intradermal Skin Testing. The following points hold true for both types of testing:
It is best to perform these tests during the season(s) when the allergy is the worst
Test should come after examination for other potential causes including:
Fungal or yeast infections
Chronic bacterial infections
* Dr. Limpach might order a 12-week hypoallergenic diet to rule out a food allergy. Food allergies are difficult to detect using either blood or skin testing methods. Nutriscan, a saliva-based test will help determine adverse food reactions, but dietary exclusion is still considered the Gold Standard.
Convenient and easy to do, a small sample of the patient’s blood is drawn and analyzed. It is then tested for a reaction to a vast array of geographical appropriate allergens, including:
Mites - house dust and grain
Insect proteins - house flies, mosquitoes, roaches
* For best results, dogs should be off all steroids and anti-histamines for at least a month before samples are drawn. Blood tests are much less invasive and time-consuming than intradermal skin tests. Blood tests are fast becoming the most popular form of allergy testing for atopy. As a veterinary dermatologist, Dr. Limpach is trained to read these results accurately.
INTRADERMAL SKIN TESTING
Intradermal skin testing is more invasive than blood testing. To perform skin allergy testing for dogs:
The patient is sedated
The patient is placed on its side
A large area on the patient’s side is shaved
Small needles inject tiny amounts of each test allergens in a specific pattern creating bumps. If the dog has an allergic reaction, the bump gets big and red. Positive reactions are graded on a scale of 1-4.
* After 10-15 minutes, the shaved area is examined to determine which allergens caused the reaction. Based on what the pattern indicates, Dr.Limpach can prescribe the most effective treatment. Skin testing can be 75% accurate, however, they can be inaccurate if patients have received antihistamines or steroids in the months leading up to testing.
Allergies can be effectively treated & managed, but not cured. There are many types of treatment including oral medication, bathing, topical therapy, and even injectable antigen therapy. Allergy medicine for dogs may involve one or more of the following types of therapies:
Treats dog allergies (atopy) with anti-inflammatory drugs such as corticosteroids, Atopica or antihistamines that block the allergic reaction
The appropriate topical therapy can treat secondary bacterial and yeast infections, provide fast relief from excessive itching, remove antigens, dead hair, dying skin cells and rehydrate the skin. There are many products now available in the form of shampoos, mousse, sprays, & spot-ons. Dr. Limpach will prescribe the most appropriate products for your dog's condition.
These modify and reduce the dog’s immune response to reduce the amount of itching which occurs from exposure to the antigens - ask us about Cytopoint injections.
These include antihistamines, corticosteroids and a new medication known as Apoquel which specifically targets the itch response by blocking the substances in the body which causes itch.
These include the use of prescription diets like Royal Canid Skin Support or VRS Protect or Transform. Strategic supplementation of nutraceuticals (fatty acids, herbs, vitamins) can go a long way to control seasonal allergies & heal the skin. These will all be discussed and considered at your consult with Dr. Limpach.
If the specific allergens are identified by testing, immunotherapy can be prescribed. This form of medicine is injectable or oral, & is usually lifelong. The oral form is called SLIT (Sublingual Immunotherapy), & requires twice-daily dosing. Injectable Immunotherapy is still available, but current research shows a better response to SLIT. Repeated dosing helps reprogram or desensitize the patient’s immune system. About 70% of treated dogs see a significant improvement. Some dogs respond so well that allergies are essentially eliminated. A small percentage of dogs respond so poorly that therapy is discontinued after a couple of years.
CHOOSING THE BEST DOG FOOD FOR ALLERGIES
Some dogs suffer from adverse food reactions or food allergies. The best way to determine which one is to do an elimination diet. We change your dog’s diet to a prescription diet formulated for diet elimination trials. We can determine if your dog has either by prescribing one of the following strategies:
Limited/Novel ingredient diet: These are prescription diets formulated with 2 main ingredients.
Hydrolyzed protein diet: These diets are “pre-digested” so the proteins in the food are broken down into amino acid components.
Nutriscan test: This is a saliva test that checks for higher than normal amounts of immunoglobulins to 24 different common diet ingredients.
* It is important to remember that only 10% of all dog allergies are true food allergies. There are many diets that are pro-inflammatory which results in the more common adverse food reaction category. Changing your dog's diet to one that is specially formulated to be highly anti-inflammatory is like giving your dog "medicine" in a bag.