How to manage allergies in dogs

By Brittany Lancellotti, DVM, DACVD

Buddy, a lively five-year-old male golden retriever, had been struggling with relentless itching and recurrent infections for months. His owner, desperate for relief, tried multiple medications with inconsistent results. A closer evaluation revealed Buddy had concurrent atopic dermatitis and food allergies, making a single medication insufficient. By tailoring his treatment with a combination of anti-inflammatory and antipruritic medications, along with a strict dietary plan, Buddy finally found relief.

This case highlights a critical point in veterinary dermatology: there is no one-size-fits-all solution for managing allergic disease. Identifying and addressing the primary allergic triggers—flea, food, and environmental allergies—is the foundation for successful long-term management.

The complex nature of canine allergies

Allergic dermatitis in dogs is primarily triggered by one or more conditions: flea allergy dermatitis (FAD), food allergies, and environmental allergies (atopic dermatitis). Proper diagnosis and targeted treatment are essential to managing these conditions effectively.

1) Flea allergy dermatitis (FAD)

FAD is a common allergic skin disease in dogs caused by a hypersensitivity reaction to flea saliva. It is characterized by pruritus, inflammation, and secondary infections typically on the dorsal rump, caudal ventral abdomen, and proximal medial thighs. Even minimal exposure can trigger severe pruritus leading to pyotraumatic dermatitis and secondary infections with bacteria, yeast, or both.

The incidence of this disease depends heavily on geographic location, as certain regions, such as Southern California and Florida, have ideal temperatures for more flea persistence throughout the year. The cornerstone of management is strict flea prevention with prescription parasiticides. Flea infestations should be controlled not only on the pet but also in the environment. Symptomatic anti-inflammatory medications can be selected based on the individual's level of inflammation and comorbidity considerations. Topical glucocorticoids are often helpful as part of a multi-modal plan for rapid, localized relief.

2) Food allergy

Canine adverse food reactions (CAFR) can present with similar clinical signs as environmental allergies, including pruritus and recurrent infections to the paws, face, ears, ventrum, and perianal skin (including anal sacs). Concurrent clinical signs may include gastrointestinal (GI) upset, conjunctivitis, sneezing, hives, or symmetric lupoid onychitis. The gold standard for diagnosis is an elimination diet trial using a hydrolyzed or novel protein diet for eight to 12 weeks. If improvement is observed, individual ingredient challenges can identify the specific allergen. If non-allergic triggers of pruritus have been ruled out, the remainder of ongoing clinical signs at the end of the elimination diet trial can be attributed to environmental triggers.

3) Environmental allergy (atopic dermatitis)

Dogs with environmental allergies react to airborne allergens, such as pollen (grasses, trees, weeds), mites (dust and storage), dander (human, cat, horse, mouse/rat), and mold. The most effective long-term treatment is allergen-specific immunotherapy (ASIT), which desensitizes the immune system to specific allergens and has been shown to reduce symptoms in 60-70 percent of dogs.¹

Symptomatic relief may also require a combination of anti-inflammatory and antipruritic medications, particularly during the induction phase of immunotherapy. While immunotherapy is effective in reducing clinical signs and the necessity of medications, consideration should be taken to adjusting medications based on how the pet is responding to immunotherapy. This allows practitioners to find the lowest effective dose of the safest effective therapies to minimize long-term adverse effects from a life-long disease. Owners should be equipped with at-home tools to manage mild flares and clear instructions on when and how to implement those tools best.

Individual plans for acute and chronic disease

Canine allergic skin disease is a multifaceted condition that requires individualized treatment. Allergies manifest in various ways, including pruritus (itching), inflammation, secondary infections, and chronic skin changes.

Selecting the appropriate therapy depends on multiple factors, including the presentation and severity of clinical signs, underlying comorbidities and tolerance to specific medications, the mechanism of action of specific medications, client concerns, and cost considerations.

Importantly, all treatment plans should begin with an evaluation of whether a flea, food, or environmental allergy is contributing to clinical signs.

Mechanisms of action: Matching drugs to clinical needs

Glucocorticoids: The rapid-fire response

Glucocorticoids (GCs) bind to glucocorticoid receptors within the cytoplasm, transport into the nucleus, and bind to glucocorticoid response elements that influence up- and down-regulation of gene transcription. This has a number of effects in acute and chronic treatment of pruritus and inflammation.

Short-term side effects are common, such as polyuria, polydipsia, polyphagia, panting, behavior changes, diarrhea, and more. Monitoring the patient's tolerance and reducing to the lowest effective dose and frequency should be prioritized if GCs are used long-term due to progressive adverse effects, including increased cardiovascular workload, immunosuppression, risk of diabetes and pancreatitis, muscle and ligament atrophy and iatrogenic hyperadrenocorticism. Long-term injectable GCs are not recommended.

Oral GCs are administered by liquid or tablet at 0.5-1.0 mg/kg prednisone/prednisolone equivalent every 24 hours initially, then lowered to the lowest effective dose and frequency that maintains remission of clinical signs.^2,3 Steroid-sparing therapies should be used to minimize long-term risks.

Topical glucocorticoids are helpful for localized treatment of skin and ear inflammation to reduce dependence on systemic steroids. Caution should be taken with potent topical steroids, such as betamethasone, fluocinolone, and triamcinolone, as repeated or chronic use may lead to hypotonic skin, milia, and secondary pyoderma.

Modified cyclosporine: The long-term controller

Cyclosporine, a calcineurin inhibitor, leads to decreased activation of T cells and a decrease in proinflammatory cytokines, such as interferon-α, to decrease both pruritus and edema in the treatment of chronic, but not acute, allergic dermatitis.^2,3

The most common short-term side effects are GI, and less common long-term risks include gingival hyperplasia, opportunistic fungal infections (less common at 5 mg/kg dosing), and papillomas.⁴

Efficacy is typically achieved within the first four weeks of administration and continues to improve in the following two to three months. Once remission is achieved, modified cyclosporine can be reduced to the lowest effective dose and frequency, and many patients can be controlled with every other day or twice weekly dosing.

Alternatively, the daily dose can be decreased. Caution should be used when administering cyclosporine concurrently with medications that can affect the cytochrome P450 enzyme system in the liver, such as ketoconazole, as this will affect the circulating concentration of cyclosporine.

Janus kinase inhibitors (JAKi): Precision itch control

JAK inhibitors decrease proinflammatory and pruritogenic cytokines IL-2, IL-4, IL-6, IL-13, and IL-31.5 JAKi reduce pruritus with minimal side effects and can be safely given with many common medications, but are not as effective at reducing edema.^6,7 They should not be used in dogs under 12 months of age due to risks of serious infection, such as demodicosis and bronchopneumonia. Novel skin masses were noted during initial safety studies, but an increased risk of neoplasia has not been found.^5,6,8

Oclacitinib is administered as an oral tablet or chewable, initially at 0.4-0.6 mg/kg twice daily for 14 days, then once daily for longer-term symptomatic management of allergic pruritus. Ilunocitinib is administered as an oral tablet at 0.6-0.8 mg/kg once daily and is recommended to be withheld 28 days before and after vaccinations due to the results of the initial vaccine response study. A subsequent study showed no serious adverse effects or decreased response to vaccine boosters.⁹

A randomized, blinded clinical trial demonstrated a similar reduction in pruritus and canine atopic dermatitis extent and severity index (CADESI)-04 scores in dogs receiving either ilunocitinib 0.6-0.8 mg/kg once daily or oclacitinib 0.4-0.6mg/kg twice daily from day (D)0-D14. Pruritus scores increased between D14 and D28 for oclacitinib and decreased for ilunocitinib.10 On D28 to D12, mean pruritus and lesion scores were significantly lower for ilunocitinib compared to oclacitinib, and a greater number of ilunocitinib-treated dogs achieved clinical remission of pruritus (i.e. pruritis visual analog scale (PVAS) score <2) with both drugs demonstrating similar safety throughout the study.¹⁰

Lokivetmab: For targeted itch relief

Lokivetmab is a canine monoclonal antibody that binds to IL-31, inhibiting its pruritogenic effects within the first three days and lasting an average of four weeks. This antipruritic can be used in dogs of any age, there are no reported side effects, and it can be administered in patients receiving other common medications or with comorbidities, but it has minimal anti-inflammatory effects.²

Cytopoint is administered as a subcutaneous injection in the veterinary clinic at 2 mg/kg once monthly or as needed and can be used for long-term symptomatic management of pruritus.

The art of combination therapy

Many allergic dogs require a multimodal approach. However, symptomatic treatments should not replace efforts to control the primary allergic trigger(s). For example, a dog with atopic dermatitis and otitis externa may benefit from a combination of lokivetmab for pruritus and topical glucocorticoids for inflammation. Still, long-term success is often most effective with allergen-specific immunotherapy for desensitization.

A patient with CAFR might need a strict elimination diet trial alongside a JAK inhibitor for symptomatic relief during the initial weeks of this diagnostic food test, evaluating for relapse of clinical signs with discontinued medications prior to challenge feeding at the end of the diet trial.

A personalized approach

There is no single "best" allergy medication for every dog. Treatment selection should be based on the presentation and severity of clinical signs, underlying comorbidities, and tolerance to specific medications, the mechanism of action of specific medications, client concerns, and cost considerations. However, treatment should always start with identifying and addressing the primary triggers—flea allergy, food allergy, and environmental allergy—before relying solely on symptomatic control.

By adopting an individualized approach and focusing on long-term allergy management, veterinarians can maximize therapeutic success and improve the quality of life for pets and their owners. As Buddy's case demonstrated, a tailored strategy leads to long-term relief and happier patients.

Brittany Lancellotti, DVM, DACVD, is the founder and host of Your Vet Wants You to Know, practices at Veterinary Skin and Ear in Los Angeles, Calif., and is a Fear Free-certified practitioner. Dr. Lancellotti graduated with honors from WesternU and enjoys teaching nationally, internationally, and virtually.

References

1. Mueller, Ralf S. "A Systematic Review of Allergen Immunotherapy, a Successful Therapy for Canine Atopic Dermatitis and Feline Atopic Skin Syndrome." JAVMA-JOURNAL OF THE AMERICAN VETERINARY MEDICAL ASSOCIATION, vol. 261, June 2023, pp. S30–35. EBSCOhost, https://doi-org.proxy.westernu.edu/10.2460/javma.22.12.0576.
2. Outerbridge CA, Jordan TJM. Current Knowledge on Canine Atopic Dermatitis: Pathogenesis and Treatment. Advances in small animal care. 2021;2:101-115.
3. Miller, WH et al. Muller and Kirk's Small Animal Dermatology. Vol 7^th ed. Saunders, 2013.
4. Archer TM, et al. Oral cyclosporine treatment in dogs: a review of the literature. J Vet Intern Med 2014;28:1–20.
5. Cosgrove SB, Wren JA, Cleaver DM, et al. A blinded, randomized, placebo-controlled trial of the efficacy and safety of the Janus kinase inhibitor oclacitinib (Apoquel®) in client-owned dogs with atopic dermatitis. Vet Dermatol 2013;24:587
6. Olivry T et al. Treatment of canine atopic dermatitis: 2015 updated guidelines from the international committee on allergic diseases of animals (ICADA). BMC Vet Res 2015;11:210.
7. Zenrelia, Freedom of Information Summary
8. Lancellotti B. et al. Age- and breed-matched retrospective cohort study of malignancies and benign skin masses in 660 dogs with allergic dermatitis treated long-term with versus without oclacitinib. Journal of the American Veterinary Medical Association. 2020;257(5):507-516.
9. King, S. et al. Serolotic Response to Core Booster Vaccinations in Dogs Treated with a Novel JAK Inhibitor. Abstract Presentation. International Society of Companion Animal Infectious Disease. 2024.
10. Forster S, Boegel A, Despa S,  Trout C,  King S.  Comparative efficacy and safety of ilunocitinib and oclacitinib for the control of pruritus and associated skin lesions in dogs with atopic dermatitis. Vet Dermatol.  2025; 00: 1–10.
11. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (7): signalment and cutaneous manifestations of dogs and cats with adverse food reactions. BMC Vet Res. 2019;15