Canine allergic disease (atopy) often presents as a skin disease, or canine atopic dermatitis. Up to 15% of dogs suffer from an atopic condition and accounts for 25% of animals referred for pruritus. Atopy is a hereditary form of allergy to pollen of plants (for example grasses, weeds, trees), fungi or various dust and storage mites.
The first symptoms typically occur between 1-3 years of age (around 75% of all cases). Sporadically, symptoms occur in animals under 6 months of age.
Dog allergy symptoms
The most obvious sign of atopy is pruritus. Commonly, dogs will lick or bite their feet and can be seen rubbing their heads along the floor or other objects. The inflammation of the skin on paws, head, armpit and groin associated with itching are important symptoms for making a diagnosis. Recurrent ear infections are also often caused by an atopy (in over 75% of cases).
Discoloration of the fur from licking and bilateral eye infection are also observed in some patients. Depending on the duration and the severity of the disorder, lesions can vary between erythema (redness), hyperkeratosis (keratinization) and lichenification (thickening) of the skin. Sneezing, watery eyes and asthma are additional symptoms. Sometimes gastrointestinal symptoms appear.
Secondary dog allergy symptoms
Atopy is often accompanied by seborrhoea sicca (dry form of excess sebaceous exudate) mixed with skin flakes and superficial pyoderma due to bacterial (Staphylococcus aureus or intermedius) or yeast (Malassezia) infection. When patients are being treated for atopic dermatitis, they should also be treated for secondary infections.
Predisposed dog breeds
Any dog can develop atopy but certain breeds are at a higher risk. Such breeds include the Lhasa Apso, Schnauzer, Boxer, Labrador, Golden Retriever, Poodle, West Highland White Terrier, Cairn Terrier, Jack Russell, Fox Terrier, Cocker Spaniel, Dalmatian, Bulldog, English Setter, Irish Setter and Chihuahua.