Allergic skin disease in dogs falls into food allergy, environmental (atopic) allergy, and contact dermatitis. Use the Dermatology AI for photo analysis and the Dermatology Specialist for workup strategies.
Allergic skin disease in dogs falls into three main categories: food allergy, environmental allergy (atopic dermatitis), and contact dermatitis. Many dogs have more than one. Clinical signs overlap—pruritus (itching), erythema, alopecia, secondary infections, and otitis—making diagnosis a process of elimination.
Food allergy is an adverse reaction to a food allergen, typically a protein. Beef, chicken, dairy, egg, wheat, and lamb are common culprits. Signs include pruritus (often non-seasonal), recurrent ear infections, and sometimes GI signs. Diagnosis requires an elimination diet trial—the gold standard is a hydrolyzed or novel protein diet for 8-12 weeks with no other treats, flavored medications, or table scraps.
Elimination Diet Protocol
Choose Diet
Choose a hydrolyzed protein diet or novel protein (e.g., venison, duck, kangaroo) the dog has never eaten.
Feed Exclusively
Feed exclusively for 8-12 weeks. No treats, chews, or flavored preventatives unless approved.
Re-challenge
Re-challenge with original diet to confirm—return of pruritus confirms food allergy.
Identify Allergen
Re-challenge individual ingredients to identify the specific allergen.
Blood and saliva tests for food allergies are unreliable and not recommended for diagnosis.
Atopic dermatitis is a genetically predisposed inflammatory skin disease driven by environmental allergens—pollens, molds, dust mites. It typically presents with pruritus of the face, feet, ears, and ventrum, often with a seasonal component. Diagnosis is based on history, clinical signs, and ruling out other causes (parasites, food, infection). Intradermal or serum IgE testing can identify allergens for immunotherapy.
Immunotherapy
Allergen-specific immunotherapy (allergy shots or oral drops) desensitizes the immune system to specific allergens. It takes 6-12 months to see benefit but can provide long-term control and reduce medication needs. Success rates vary; many dogs show significant improvement.
Apoquel (oclacitinib) is a Janus kinase inhibitor that blocks itch pathways. It works within hours and is given orally twice daily initially, then once daily for maintenance. It is not for use in dogs under 12 months or with serious infections. Cytopoint (lokivetmab) is a monoclonal antibody that neutralizes IL-31, a key itch cytokine. It is given as a monthly injection and has minimal systemic side effects. Both are effective for atopic itch; choice depends on owner preference, cost, and concurrent conditions.
Contact dermatitis occurs when the skin reacts to a topical allergen—cleaning products, plants, bedding, or topical medications. It often affects sparsely haired areas (ventrum, groin). Removal of the allergen and topical therapy usually resolve the issue.
Persistent itching, hair loss, red skin, ear infections, or any skin change warrants a veterinary exam. Secondary bacterial or yeast infections are common and require treatment. Consider referral to a veterinary dermatologist when: diagnosis is unclear, the dog fails to respond to standard therapy, recurrent infections persist, or immunotherapy is being considered.
Warning: Do not use human antihistamines or topical products without veterinary guidance—some are toxic to dogs.
- Food, environmental, and contact allergies overlap in signs; diagnosis is by elimination.
- Elimination diet requires 8-12 weeks exclusively on hydrolyzed or novel protein—no treats.
- Blood/saliva allergy tests are unreliable; elimination diet is the gold standard.
- Apoquel and Cytopoint effectively control atopic itch; immunotherapy takes 6-12 months.
- Refer to a dermatologist when diagnosis is unclear or standard therapy fails.