ITCHING AND SCRATCHING

Allergies to things in the environment, whether it’s dust mites, pollen, mold, trees and grasses, fleas, or even your unsuspecting household cat, is called allergic dermatitis. Allergic dermatitis is also known as atopy, allergic inhalant dermatitis, seasonal allergy, or environmental allergy. Whatever it’s called, the manifestation is red skin, “hot spots,” ear infections, recurrent skin infections and scratching like mad. The development of allergic dermatitis requires two things: a dog with a genetic predisposition to developing allergies and an allergen in the environment to incite the allergic response. Allergic dermatitis is a complicated disease and often requires complicated therapy.

Complicated cause
At least three mechanisms play a role in allergic dermatitis in dogs. First, the environmental allergen causes the release of histamine from a cell known as a mast cell, which sets off an allergic reaction. T-cells have a yin-yang effect on the immune system, both ramping up the immune system and blocking a protective effect against allergies. Finally, normal skin protects the body from invasion by allergens. Dogs suffering from allergic dermatitis likely have impaired function of the skin cells, allowing allergens access and predisposing your dog to yeast and bacterial infections. The net effect of all this cellular hysteria?  An itchy dog! 

Complex treatment regimen
Given the complexities described in the pathways leading to allergic dermatitis, don't be surprised if you receive a small pharmacy’s worth of prescriptions when your dog is diagnosed with allergic dermatitis. What follows is a brief description of some of the more common medications used to treat allergic dermatitis.
1. Although the role of histamine is limited in canine allergic dermatitis, antihistamines, if they decrease itchiness, are very safe and cost effective.
2. Shampoos play multiple roles in the management of allergic dermatitis. Bathing your dog is soothing to the skin and decreases surface allergens, and medicated shampoos decrease surface bacteria and yeast. 
3. Antibiotics and anti-yeast medications are critical in controlling secondary infections in the skin of itchy dogs. The function of deregulated T-cells can be modified by the use of immunosuppressive agents, most commonly steroids, and more recently cyclosporine.
4. Finally, dogs can get allergy shots, a form of immunotherapy where the immune system is gradually desensitized to the offending allergen. This form of treatment can often dramatically improve the dog’s quality of life by decreasing their itchiness and skin and ear infections.

What a pet owner can do
If your dog is scratching, see your veterinarian. When your itchy dog needs a vet with a specialized skill to manage their allergic dermatitis, see a dermatology specialist. You can find a board certified dermatologist on the American College of Veterinary Dermatology website.
If your dog is scratching a lot, hopefully one or more of the treatments described can help make your dog be more comfortable in these waning summer months.