Introduction
Atopy is a common clinical syndrome that involves immune-mediated hypersensitivity (allergy) with a hereditary predisposition. Also known as allergic inhalant dermatitis, atopic dermatitis, and atopic eczema, canine atopy is characterized by chronic pruritus (itchiness), often seasonal, primarily of the feet, face, and underbelly. It commonly is associated with self-inflicted trauma from scratching by the affected dog at the atopy site. Secondary skin afflictions are also common. Atopy is reported to be one of the most common allergic skin disorders in dogs, perhaps second only to flea bite hypersensitivity and possibly food allergies.
Symptoms of Atopy in Dogs
Atopy is a genetically-influenced disorder causing dogs to develop a hypersensitivity to one or more normally innocuous environmental allergens that are either inhaled or absorbed through the skin. The mode of inheritance is unknown, and other factors may influence the development of atopy in addition to genetics. Common contributors to atopy include pollens (from grasses, weeds, trees or other plants), molds, household dust mites, animal dander, chemicals, and innumerable other environmental allergens. There is marked geographic and seasonal variation in exposure to potential allergens. Unfortunately, most dogs with seasonal atopy eventually progress to having nonseasonal disease.
There is no clear sex predisposition, although atopy seems to be slightly more common in female dogs. While the age of onset can vary widely, atopy is most frequently first seen in young dogs between 1 and 3 years of age. Certain breeds are predisposed, including Chinese Shar-peis, Cairn terriers, West Highland white terriers, Boston terriers, Scottish terriers, Sealyham terriers, Lhasa apsos, Shih Tzus, Wire-haired fox terriers, English bulldogs, Pugs, Dalmatians, Irish setters, English setters, Golden retrievers, Labrador retrievers and Miniature schnauzers.
The most common and consistent clinical sign of atopy is intense scratching, precipitated by pruritus - or itchiness - of the skin. The hallmark itching, scratching, licking, biting, chewing, and rubbing usually are focused on the face, feet, and belly areas. Other commonly affected areas are the base of the tail, the groin area, around the eyes (periocular region), around and inside the ears, under the front legs (the so-called “armpits”, more medically referred to as the axillary region), between the toes (the interdigital spaces), on top of the feet and on the muzzle. Atopy often is so severe that it interferes dramatically with a dog’s quality of life.
In addition to pruritus, many atopic dogs have recurrent ear infections. Their ears often become swollen, irritated, and inflamed, and in many cases they develop a nasty “yeasty” odor with profuse amounts of abnormal wax and other aural discharge. In severe cases, the effects of atopy lead to bumps, scabs, and “hot spots” on the skin. These lesions often develop secondary bacterial or yeast infections, making diagnosis and treatment of atopy more difficult. Saliva staining of hair is very commonly seen. Most clinical signs associated with atopy worsen with time.
Atopy cannot be “cured,” but normally it can be controlled. If your dog suffers from these clinical signs, schedule an appointment with your veterinarian as soon as you can.