Atopy

Abstract

PHOTOS 1-7: Atopy is a hypersensitivity reaction to inhaled or cutaneously absorbed allergens in genetically predisposed animals. Atopy causes animals to become sensitised to environmental allergens by producing allergen specific IgE. It is a common condition in dogs and mostly appears between one and three years of age. The initial symptoms include pruritis which causes licking, chewing, scratching and rubbing. The pruritis may be seasonal depending on the allergen. The feet, flanks, groin, axillae, face and ears are usually affected. Self trauma results in secondary lesions such as salivary staining, alopecia, excoriations, scales, crusts, hyperpigmentation and lichenification. Secondary Malassezia dermatitis and otitis externa are common. It may also lead to chronic acral lick dermatitis, recurrent pyotraumatic dermatitis, conjunctivitis, hyperhidrosis, allergic bronchitis and rhinitis. Diagnosis of canine atopy is done via allergy testing and dermatohistopathology. Controlling the secondary infections caused by atopy is an important part of treating this condition. Pruritis can be controlled with topical and systemic therapies. Oral essential fatty acid supplementation may also help to control the pruritis. The prognosis is good but lifelong therapy to control the condition is usually needed.

REFERENCES: PHOTOS 1-7: Medleau, L & Hnilica, KA 2006, ‘Small animal dermatology: a color atlas and therapeutic guide’, 2nd ed., Saunders Elsevier, St. Louis, pp.162-166.