The most common reasons for allergies are fleas and other environmental elements. Other less common sources are food allergy and contact dermatitis (allergens). The target organ in dogs is the skin, and often the area involved will suggest the reason for the reaction. While this is helpful, it is not absolute, and often patients have multiple types of allergies or may have crossover symptoms.
Allergic contact dermatitis is an allergic reaction that is often caused by chemicals or products that contact your pet’s skin. This can include detergents, soaps, natural and synthetic fibers, paint, cleaning products, insecticides, and in some cases, even tall weeds. In dogs, most contact dermatitis is limited to the skin on the underneath surface of the body. This may be limited to the groin and inside of the legs or may extend up the body to the axillar area. Excessive itching, redness, and irritation are the most common symptoms at and around the site of contact. Often these reactions occur quickly, with secondary bacterial infections occurring nearly overnight. Secondary symptoms may also appear, such as hair loss, sores, scabbing, and hot spots.
Apoquel, a JAK inhibitor, is most commonly used in the short term to calm the reaction. Antibiotics are used if secondary infection is present. The ultimate treatment, in such cases, is to determine the offending agent and remove contact potential from the dog.