The approach to the pruritic dog Work-up of infectious and allergic causes for pruritus in dogs (part 1)

摘要

Pruritic skin diseases are a common cause for attending a veterinary practise. Many pruritic diseases look alike; therefore, a systematic approach to the pruritic animal is highly recommended. Initially, parasitic, bacterial and fungal infections should be ruled out or treated (these diseases will be discussed in a subsequent article) before an allergy workup is planned. Favrot's criteria for canine atopic dermatitis (CAD) are helpful for the clinical diagnosis of this disease. The exclusion of ectoparasites and infection is followed by an elimination diet trial, especially if an animal is itching all year round. Elimination diet trials consist of exclusively feeding one novel protein and carbohydrate source over 10-12 weeks. Once the inflammation and pruritus subside, the diet trial is followed by provoking the dog with its previous food items. If pruritus and dermal inflammation reoccur, the diagnosis of food-induced atopic dermatitis is confirmed. If the pruritus persists despite a strict diet trial or if the provocation test remains negative, the diagnosis is canine atopic dermatitis sensu stricto. In this case, an allergy test can help to reveal the contributing allergens. Allergen-specific immunotherapy or symptomatic medications to control itch and inflammation are helpful in the long-term treatment of chronic allergic dermatitis.