Chairside Roadmap to Diagnosing Canine Atopic Dermatitis

Canine Atopic Dermatitis (CAD) is one of the most common skin disorders veterinarians encounter in India, and timely, accurate diagnosis is critical for effective management and client satisfaction. This guide focuses on practical, chairside strategies to help you identify CAD efficiently and make informed clinical decisions. 

Why Understanding the Allergy Mechanism Matters 

CAD is mostly driven by a type-1 hypersensitivity reaction mediated by IgE. Environmental proteins, commonly called allergens, trigger an exaggerated inflammatory response, leading to itching, recurrent infections, and sometimes hives or respiratory signs¹. 

Key points for practice: 

• Dogs can react to multiple allergens simultaneously (co-sensitization), especially if proteins are structurally similar¹.  

• Recognizing cross-reactivity helps guide allergen testing and therapy.  

Favrot’s Criteria: Your First Chairside Tool 

Before any lab tests, Favrot’s criteria allow quick, reliable CAD screening². There are two sets of criteria, and meeting ≥5 out of 8 suggests a high likelihood of CAD¹. 

Set 1 highlights: affected ears and front feet, onset <3 years, recurrent infections, corticosteroid-responsive itching, mostly indoor dogs. 

Set 2 highlights: affected ears and front feet, onset <3 years, mostly indoor, pruritus at onset, with non-affected dorso-lumbar area. 

Practical tip: Combine Favrot’s criteria with CADESI scoring and Pruritus Visual Assessment Score (PVAS) for a more complete clinical picture¹. 

Choosing the Right Diagnostic Test 

1. Intradermal Test (IDT)^1,3 

• Gold standard in dogs 

• Use individual, standardized allergen extracts rather than mixtures to avoid false negatives 

• Adjust concentrations carefully to avoid irritant reactions 

• Combine objective scoring (0–4 scale) with clinical judgment for interpretation  

2. Serologic Allergen Test (SAT)^1,4 

• Measures allergen-specific IgE in blood  

• Useful if IDT is not feasible, but results vary with helminth infections and co-sensitization  

• Should be interpreted in context of clinical signs  

3. Skin Prick Test (SPT)^1,5 

• Less invasive, no sedation needed  

• High specificity but moderate-to-low sensitivity; limited use in dogs  

• Consider for quick chairside screening or research  

4. Patch / Challenge Tests¹ 

• Rarely used; mainly for research or food allergens 

• Risk of adverse reactions makes them impractical for routine practice  

Local Allergens That Matter in Indian Dogs 

Tip: Adjust allergen panels based on geography, season, and indoor habits to maximize test relevance¹ 

Chairside Tips for Accurate CAD Diagnosis 

1. Start with Favrot’s criteria for immediate clinical assessment  

2. Confirm with IDT using individual standardized allergens  

3. Use SAT as a complementary tool if IDT is not feasible  

4. Interpret results considering co-sensitization and cross-reactivity  

5. Tailor allergen panels to local Indian conditions for best outcomes  

Conclusion 

Diagnosing CAD is part art, part science. While there are sophisticated tools like IDT and SAT, the clinician’s judgment remains central, particularly in India, where environmental and geographic factors strongly influence allergen prevalence. Reliable, standardized diagnostic protocols are still needed, and cross-reactivity must always be considered.  

References  

1. Morales-Romero R, Gonzalez-Dominguez MS, Sánchez J, Correa-Valencia NM, Maldonado-Estrada JG. Efficacy of diagnostic testing for allergen sensitization in canine atopic dermatitis: a systematic review. Frontiers in Veterinary Science. 2025 May 21;12:1551207. https://doi.org/10.3389/fvets.2025.1551207  

2. Abilova ZB, Zhabykpayeva AG, Rychshanova RM, Suleimanova KU, Khassanova MA, Zhabykpayeva DA. Diagnostic Approaches and Comparative Effectiveness of Modern Methods for Treating Atopic Dermatitis in Dogs. HERALD OF SCIENCE OF S SEIFULLIN KAZAKH AGRO TECHNICAL RESEARCH UNIVERSITY: Veterinary sciences. 2025 Dec 30(4 (012)):19-33. https://bulletinofscience.kazatu.edu.kz/index.php/veterinary-science/article/download/2104/1474  

3. Fischer NM, Müller RS. Allergen specific immunotherapy in canine atopic dermatitis: An update. Current Dermatology Reports. 2019 Dec;8(4):297-302. https://dermcare.com.au/wp-content/uploads/2024/08/Allergen-Specific-Immuno-in-CAD-update-2019.pdf  

4. Chermprapai S, Thengchaisri N. A descriptive study of allergen-specific IgE serological tests for canine atopic dermatitis in Thailand. BMC veterinary research. 2020 Dec 7;16(1):475. https://link.springer.com/content/pdf/10.1186/s12917-020-02684-x.pdf  
5. Carmona-Gil AM, Sánchez J, Maldonado-Estrada J. Evaluation of skin prick-test reactions for allergic sensitization in dogs with clinical symptoms compatible with atopic dermatitis. A pilot study. Frontiers in veterinary science. 2019 Dec 17;6:448. https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2019.00448/pdf