Diagnosing and Treating Environmental Allergies in Dogs

Atopy, also called Allergic Dermatitis, is an inflammatory, typically itchy condition of the skin that results from environmental allergies. In atopic dogs, their skin barrier is defective and this allows the allergens to penetrate deeper into the skin resulting in itching and irritated skin. Infections with yeast and bacteria commonly occur since the skin barrier cannot defend against them as they should normally. This can be seasonal or year-round.

Why Did My Dog Develop Atopy?

Genetics, environmental exposures, and certain breeds are more predisposed. Dogs that live in cities are more likely to develop atopy. Dogs that are exposed to smoke frequently are also at higher risk for allergies.

Breeds, including West Highland White Terriers, Boxers, Labrador Retrievers, Golden Retrievers, German Shepherds, Shiba Inu, Pit Bulls, Rhodesian ridgeback, Bull Terrier, Shar Pei, Vizsla, Cairn Terrier, French Bulldog, Chows, Cocker Spaniel, Irish Setter, and Shih Tzu’s are more likely to develop allergies. However, any breed or mix-breed can be affected.

How Do You Diagnose Allergic Dermatitis in Dogs?

There is no one specific test to diagnose atopy. Typically, clinical symptoms and response to treatment allow for a diagnosis to be made. If your dog has 5 of these things, they likely have atopy:

1. Itching and/or skin/ear infections developed before they were 3 years old

2. Spend a lot of time indoors

3. Itching and inflammation improves when on steroids

4. Itching

5. Chewing on or licking paws, especially front paws

6. Ear flaps get red or ear infections develop intermittently

7. There are no crusted areas along the ear flap margin

8. Not just itching at the tail base

Most atopic dogs will itch and have lesions around the eyes, around the mouth, in the axillary area (armpits), inguinal area (groin region), belly, and around the rectum.

The skin can be red, thickened, crusty, have pustules (pimple appearing lesions), irritated ears, and lick more at the flexor surface of the joints (where the limb bends) and licking or chewing of the paws.

There are blood allergy tests and intradermal skin tests available to help figure out what your dog may be allergic to. The intradermal skin test is considered more reliable; however, this often requires referral to a specialist, sedation, and shaving a large area of fur for the injections to be administered. Dogs with clinical symptoms of atopy and unaffected dogs can have positive reactions to these allergy tests, so it can’t truly diagnose atopy.

What Are Other Possible Causes for Itching and Abnormal Skin/Coat?

Your vet will likely want to look for other causes of itching and skin irritation to be sure nothing else is causing the symptoms.

1. Ringworm - a fungal infection
2. Fleas or Flea Allergy Dermatitis
3. Mange Mites - Scabies can cause severe itching and can also infect people
4. Food Allergies
5. Primary yeast or bacterial infections
6. Contact Allergy - allergic to new bedding, detergent, etc.

How Can I Treat My Dog's Environmental Allergies?

It’s important to understand there is no cure for atopy, just management. Even with great treatment, your pet will have occasional flare-ups. The goal of treatment is to reduce the frequency and intensity of these flare-ups.

1. Avoid what your dog is allergic to. For example, if your dog is allergic to wool, remove the wool blankets and rugs from the house.
2. Wipe off your dog’s skin and paws after she comes inside to remove as many allergens and irritants from the skin before they can do more harm.
3. Bath your dog twice weekly during her allergy season. Your vet can prescribe a medicated shampoo to help reduce itch, improve the skin barrier, treat yeast and bacterial infections, and soothe the skin. Be sure to discuss shampoo options with your vet as this is a great option to have on hand at home and use during flare-ups.
4. Consistent good flea control in case flea allergies are also an issue
5. Medications to reduce the immune system’s over-response to allergens like steroids or other immunomodulating drugs
6. Antigen-injections or oral drops
7. Omega Fatty Acid supplementation to reduce inflammation and improve the skin barrier

Steroids used to be the main drug type used to treat atopy and give itch and inflammation control. Unfortunately, steroids can have a lot of negative short and long term side effects

Luckily, there are new drug types available to reduce itching and make your dog much more comfortable with few side effects. There are pill and injectable options so be sure to discuss alternatives to steroids with your vet.

Antigens are available as injections or liquid drops in the mouth. These antigens are based on your dog’s blood or intradermal skin test results or a pre-made regional specific antigen can be tried. It will take months for these to really help, so be patient and give it time to work. The goal of the antigens is to expose your dog’s immune system to the things it is allergic to and slowly reduce that overreaction.

Read more:

Ditch the Itch: Skin Allergies in Dogs

Allergies: Atopic Dermatitis (airborne)

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