Dealing with an itchy allergic dog can be a frustrating experience for pet owners and veterinarians alike! It is frustrating because there is no cure and there is no one magic pill that works for every dog. Even diagnosing pet allergies can be far from straightforward. In addition, it is fairly common. All that biting and scratching can take a strain on everyone in the household, but with some persistence and patience an allergy program can be formulated to provide a little relief for everyone.
Kinds of Allergies
-Environmental allergies: True allergies are clinically referred to as Atopic Dermatitis (AD). With this disease pets develops antibodies inappropriately to things in the environment, such as pollens of grasses, trees, and weeds, as well as mold spores, house dust, dust mites, fleas and even other animals, like your cat! Because pet allergies can be difficult to treat, I always recommend pet owners invest in pet insurance while their pets are still young. Enrolling pets while they're still puppies and kittens may help cover costs for veterinary care throughout the pets' lives without the worry of exclusion of preexisting conditions.
The route of absorption of the allergen is thought to be through the skin. The pet's body reacts to the allergens as if they are something dangerous, mounting an allergic response, complete with the release of histamine and other inflammatory mediators which cause itchiness.
-Flea allergies: Flea allergies can occur even if you don't see fleas on your dog. A true flea allergic dog will 'flare up' with even one bite from a flea. 100% flea control is essential for the flea allergic patient. A product such as Revolution can help, as it is labeled for use in flea allergies. A flea control program should be used all year round in the flea allergic patient.
-Food allergies: About 5% to 10 % of allergic dogs are allergic to something in their food, most commonly chicken, beef, corn and wheat. A truly food allergic dog will need to be switched to a hypoallergenic dog food, not just a different brand. Most dog foods have very similar ingredients, for example beef and wheat. These are good quality ingredients, unless your dog is allergic to them. A hypoallergenic pet diet will also be processed in a plant that doesn't process food with the offending ingredients. Work with your veterinarian to find a type of food that will work for you. A true diet trial needs to be performed for at least 6 to 8 weeks, with no treats or people food before a food allergy can be ruled out as a cause for itching.
How do allergies typically present?
Most patients present with varying degrees of itchiness. The area on the body that the pet is itchy can anecdotally be helpful; flea allergies tend to be itchy along the tail base, food allergies on feet, ears and bottom, and environmental allergies tend to be seasonal and affect the inner thighs, armpits and ears. This isn't always the case though. Often there can be infection on the skin due to self trauma, causing redness, crusts and scabs, rashes and darkening of the skin. Ear infections are common as well.
Is there anything else it could be?
Yes! This is why it is very important to work with your veterinarian towards a treatment plan. Your vet will want to treat for any underlying infection, either fungal or bacterial, and consider parasites such as mites. While it is true that an allergic dog may be more predisposed to getting these types of infections, the infections themselves can cause itchiness, and need to be treated prior to properly diagnosing a dog as allergic.
How is it diagnosed?
There is no one magic diagnostic test for AD. Determining your dog has allergies is based on the history and clinical signs. There are tests that are very helpful, for example, skin scraping to rule out mites, cytology of ears to rule out ear infections, fungal cultures and trial treatment for fleas or mites are an example of a few tests your veterinarian may want to perform.
Once allergies are diagnosed, intradermal/skin or serum/blood allergy testing can be helpful as well. These tests can be pricey, which is again, why I recommend dog and cat insurance to my clients before a pet health issue arises. Both of these tests not used to diagnose allergies, but rather used to determine what the allergic patient is reacting to in order to formulate allergen-specific immunotherapy, or 'allergy shots' (see treatment section for additional information).
Biopsy or histopathology can be useful to support and diagnosis of AD, or to rule out other possible underlying problems, but is not the preferred method for allergy diagnosis.
How is it treated?
There is no one magic pill that will fix every itchy dog's problem. Often there is a frustrating trial and error period to determine which combination of therapy will work for your pet. The most common therapy includes one or more of the following:
Antihistamines: Antihistamines work by stopping the release of histamine and other inflammatory mediators. They are less likely to work with an acute flare up, and more likely to help with chronic use. Most pets' symptoms can't be controlled with an antihistamine alone, but since most are safe and fairly inexpensive, this is a good medication to try.
Steroids: Steroids are often the cornerstone of allergic therapy. Most allergic pets will respond well to anti-inflammatory doses, but long term use isn't desirable. For flare-ups, a course of steroids is indicated, but chronic use can lead to weight gain, excessive thirst, muscle weakness and laxity and other potential complications.
Atopica/Cyclosporine: This drug works by changing the body's immune response to the allergens, basically acting as an immunosuppressant. It works successfully in about 60% of patients and is safe for long term use.
Allergy shots/ immunotherapy: This treatment involves giving an injection that has been formulated specifically for your pet following allergy testing, by either intradermal or serum testing. Generally this is done for life. It is estimated that 60% to 80% of animals will improve with allergy shots.
Shampoo/Sprays: Topical products such as allergy shampoos can work by protecting the lipid barrier of the skin and by removing contact allergens from the skin. Some sprays contain a topical steroids, which are good for short term use, but shouldn't be overused chronically. Other sprays also work at protecting the skin's barrier system without the use of steroids, and can be used more long term.
Diet: Especially in dogs with non-seasonal allergies, a diet trial is necessary to rule out a food allergy. Some environmentally allergic pets seem to benefit from hypoallergenic food, even if they aren't truly food allergic. A diet trial needs to be performed for at least 6 to 8 weeks with a certified hypoallergenic diet consisting of a novel, or new protein source that the dog hasn't been exposed to, such as buffalo, venison or lamb. A prescription hydrolyzed diet can also be utilized.
Supplements: Essential Fatty Acid supplementation, or omega 3's derived from products such as fish oil can be beneficial by integrating into the cell membranes of the skin, making them more resistant to allergies. Omega FA can also help antihistamines to work better.
Flea medication: Using chronic flea medication can help rule out and treat a flea allergy. Some products, such as Revolution can actually help reduce numbers of environmental dust mites as well, benefiting dogs that are allergic to them.
With some dedication and persistence, allergies can be treated successfully. It will undoubtedly require many trips to the vet's office, and treatment will be long term. Your pet will undoubtedly have occasional flare-ups. Veterinary medicine can be expensive; consider finding the best pet insurance plan for your pet before a problem develops, which may help ensure they receive the best care, unhindered by financial constraints.