Canine atopic dermatitis (CAD) is a chronic, relapsing allergic skin disease affecting up to 10-15% of dogs. It causes significant welfare compromise through persistent pruritus, skin lesions, secondary infections, and profound impacts on quality of life for both dog and owner.
CAD involves a complex interaction between genetic predisposition, skin barrier defects, environmental allergens, and immune dysregulation. Defective filaggrin and ceramide production impair the epidermal barrier, allowing allergen penetration. Sensitised immune cells produce excessive Th2-type responses, with IL-4, IL-13, and IL-31 driving the itch-scratch cycle. IL-31 is now understood as a primary itch mediator.
CAD typically presents between 6 months and 3 years of age. Primary signs include pruritus, erythema, and self-trauma at predilection sites: paws, face, ears, axillae, groin, and perineum. Chronic changes include lichenification, hyperpigmentation, and alopecia. Secondary bacterial (Staphylococcus pseudintermedius) and yeast (Malassezia) infections exacerbate symptoms and pruritus, creating a vicious cycle.
Chronic pruritus is deeply distressing for dogs—the relentless urge to scratch disrupts sleep, feeding, play, and social interaction. Validated welfare assessment tools (CADESI, PVAS, VAS) measure both owner-perceived itch and clinical lesion severity. Research demonstrates that poorly controlled CAD significantly impairs dog quality of life, equivalent in impact to moderate chronic pain.
Diagnosis follows Favrot's criteria and involves ruling out other causes of pruritus (fleas, food allergy, sarcoptes, Malassezia). Intradermal testing and serum allergen-specific IgE testing identify allergens for immunotherapy but are not required for diagnosis. Food trial (strict elimination diet for 8-12 weeks) rules out food-induced allergic dermatitis.
Modern CAD management includes highly effective targeted therapies. Oclacitinib (Apoquel) inhibits JAK1-dependent cytokine signalling, providing rapid itch control within hours. Lokivetmab (Cytopoint) is a monoclonal antibody neutralising IL-31, providing 4-8 weeks of itch relief per injection. These therapies have transformed CAD management, allowing sustained welfare improvement with excellent safety profiles.
Allergen-specific immunotherapy (ASIT) involves administering increasing doses of identified allergens to modify immune responses. It is the only disease-modifying treatment for CAD, potentially achieving long-term reduction in allergen sensitivity. Response rates of 50-70% partial to complete remission make it the gold standard approach in appropriately selected cases.
Regular bathing with moisturising, ceramide-containing shampoos restores barrier function and removes allergens. Essential fatty acid supplementation (omega-3, omega-6) improves skin barrier integrity. Environmental allergen reduction—dust mite covers, regular washing, air filtration—reduces allergen load. Flea prevention is mandatory, as flea allergen allergy commonly co-exists with CAD.
CAD is lifelong and progressive in most dogs. Owners require education about trigger identification, early intervention at flare signs, and consistent preventive care. Multi-modal approaches combining immunotherapy, topical care, environmental management, and targeted systemic therapy achieve the best welfare outcomes. Regular veterinary monitoring tracks disease progression and adjusts therapy accordingly.