As we find ourselves in the middle of the summer allergy season for much of the continental U.S., and with the “fall flare” right around the corner, this is a great time to discuss the impact canine atopic dermatitis has on our clients and patients. Canine atopy is a frustrating disease for both clients and veterinarians alike. It is a chronic and progressive condition with many clinical presentations. Clinical recognition and correct diagnosis are key to implementing early intervention. Veterinarians need a solid understanding of the available therapeutic options to make appropriate recommendations for patients. Additionally, understanding our clients’ perspectives is key to devising successful management plans that fit their needs and desired outcomes. Clinical presentations of atopy are the most common reasons clients seek veterinary care for their dogs. Atopic symptoms and associated veterinary visits increase during peak allergy season. In a nationwide survey of veterinarians and dog owners, two out of three dog owners report worse symptoms during allergy seasons, and 56 percent say they treat their dog more often during these times.1 In the same survey, clients report waiting up to six weeks after symptoms have started prior to seeking veterinary care, using, on average, two types of treatments, spending roughly $200 more on therapy, and 75 percent of them report needing more affordable options. These statistics are skewed more toward the negative extremes in what have been coined “America’s Itchiest Cities.” Surveys, such as the one cited, provide valuable insight and highlight the impact atopy has on our clients and their pets. Data from Elanco’s America’s Itchy Dogs survey. Arriving at the correct diagnosis There are no pathognomonic clinical symptoms or historical clues that allow a definitive diagnosis to be made upon initial examination.2 Also, an understanding of recurrence rate and symptom persistence is needed prior to making a diagnosis to ensure natural variation of symptoms is not misinterpreted as effective treatment. A diagnosis of atopy is a clinical one and made via a process of elimination. Although “allergy testing” exists, it is important to note the use of these tests as a sole diagnostic can lead to a misdiagnosis and should only be performed once a clinical diagnosis of atopy has been reached and allergen-specific immunotherapy is desired. The author uses a checklist approach to allergic dogs for several reasons: The first is ensuring a complete history has been acquired and all potential differentials have been considered. The client is informed about the disease and how a diagnosis is made, and they are provided with time and space to adequately recall their pet’s disease progression and response to prior therapies. The author facilitates time for client questions, allowing them to be properly informed and empowered to make the best decision for their situation. The first step of the checklist is to identify any secondary infections. Infections may directly cause the pet’s pruritus or intensify the sensation. Resolution of these secondary issues, along with recognition that they occur as a result of underlying issues, is instrumental in the diagnostic process. The second step is to consider if a non-allergic condition, such as endocrinopathy, an immune-mediated condition, or a neoplastic disease, is responsible for the clinical presentation. These conditions may mimic atopy by causing secondary infections or pruritus. If suspected, they are most often confirmed via blood work or biopsy. The next step is to determine whether flea allergy dermatitis or another contagious parasite is causing the patient’s symptoms. Ectoparasites are a common cause of pruritus in dogs and should always be suspected in acute presentations or difficult-to-control flares in previously diagnosed atopic patients. Although isoxazolines are widely considered the ideal treatment, many preventative products are effective for flea control and parasite elimination trials. An understanding of all available products (all-in-one endectocides, single-agent oral ectoparasiticides, topical preparations, and collars) is important to provide options that meet individual client preferences and needs. Clinicians should be mindful of the flea life cycle and their geographic region when considering appropriate therapeutic trials. Most of the products that can be utilized for flea treatment programs are sufficient for ruling out other pruritic parasites. However, individual product labels and reference texts should be consulted to ensure adequate parasite coverage based on clinicians' differentials. Once non-allergic causes and parasites are eliminated, a cutaneous adverse food reaction (CAFR) should be considered in patients with nonseasonal recurrent symptoms. Additional symptoms and historical clues consistent with CAFR are a patient not responding well to anti-pruritic medications, concurrent gastrointestinal symptoms, or clinical signs beginning outside typical atopy development timeframes.3,4 No one historical clue is definitive or always indicative of a CAFR, but a combination of the preceding historical clues should raise the clinician’s level of concern. Although much effort has been directed toward the development of a diagnostic test to aid in the diagnosis of a CAFR, to date, the only effective diagnostic procedure remains a diet elimination trial with subsequent provocation testing.5 Just as there is no definitive commercial test for CAFR in dogs, there is also no definitive diet that is effective 100 percent of the time. Diet selection should ideally be based on patient history and dietary needs. A diet elimination trial should last at least eight weeks in canine patients.6 Achieving this length of time in some patients can be difficult, and a brief course of glucocorticoids or other anti-pruritic agents can be helpful during the initial phases of the diet elimination trials.7 Therapeutic management of the atopic patient A key step in achieving therapeutic success with patients that have been diagnosed with atopic dermatitis is to stress to the client that the condition is a chronic progressive disease that will require lifelong management. It is also important to set realistic goals for the clients. Atopy management goals include decreasing severity of flares, spacing flares out, preventing urgent care visits, reducing antimicrobial usage, and decreasing treatment costs over time. Clients should be provided with all therapeutic options before treatment choices are made so they can make informed decisions. This includes communicating the pros and cons of different therapy modalities, the length of time needed to assess efficacy, acknowledging monthly costs of therapeutics, their administration routes, and the logistics of repeated clinic visits for therapies, such as lokivetmab.8 Many client-related issues encountered with atopy stem back to unrealistic expectations, not understanding there are options, or not being up front with treatment-related logistics and costs. Once a mutual decision is reached, the client should be informed that this is a starting point, and finding the ideal therapy for their dog may require a little bit of trial and error. Remember, there is no one option that works for every owner or their pet, and the ideal therapy may change with time. Therapeutic options for disease intervention consist of supportive, preventative, and disease-specific options. These therapies may be instituted as a monotherapy or part of a multimodal approach. Options, such as antihistamines, fatty acid supplementation, specialty-formulated diets, and palmitoylethanolamide, should only be considered in very mild cases to keep the patient rested or as part of a multimodal protocol combined with a disease-specific therapeutic. These therapies are relatively safe but are not appropriate for an acute flare and may add unneeded patient cost. Topical therapy (bathing and barrier restoration) is a mainstay for managing any atopic patient and may provide immediate, short-lived symptom relief. It removes allergens from the hair coat, rehydrates the skin, and delivers barrier restorative products. Allergen-specific immunotherapy (ASIT) is a safe option as it lacks the adverse effects associated with most pharmaceuticals. ASIT may benefit 60-70 percent of patients, with improvement noted between six to 18 months. 15,16 When a response is seen, treatment is usually lifelong and tapered to decrease cost. There are several routes for administering ASIT, with subcutaneous injections or sublingual immunotherapy being the most common. ASIT may prevent disease progression and long-term drug requirement. It is not effective for all patients, and response varies. The most common adverse event, regardless of administration route, is increased pruritus. Application site discomfort, swelling, and, in very rare instances, anaphylaxis, urticaria, and angioedema may be encountered. During the initial induction course of ASIT, symptomatic therapy will often be needed, and concurrent use of other disease-specific therapies is utilized. Anti-IL-31 monoclonal antibody therapy (lokivetmab) has been shown to be effective in the management of canine atopic dermatitis. 14 It is primarily beneficial for decreasing pruritus associated with the disease, and patient selection is critical to therapeutic success, as the biologic has a narrower spectrum of cases where it may be favorable as a monotherapy. Clinical investigations have revealed variable success rates, with most patients experiencing an onset of action within 72 hours.9 Additionally, maximal efficacy may not be observed until subsequent injections (three total) have been administered. Major advantages of this type of monoclonal antibody therapy are that it can be administered to any age of dog, given with concurrent medications, and used with numerous comorbidities. Cost and monthly clinical visits are drawbacks of this intervention. Janus kinase (JAK) inhibitor therapy is an attractive treatment option as it offers an at-home medication option with a rapid onset of action. There are currently two U.S. Food and Drug Administration (FDA)-approved products (ilunocitinib, oclacitinib) with the same label indication. This medication category possesses both antipruritic and anti-inflammatory action, which are important to managing multiple presentations of the disease. This drug class provides its mechanism of action through interfering with cytokine signaling involved in the pathogenesis of atopy. JAK inhibitors have short half-lives and reversibly inhibit the enzyme pathway, which provides them with an overall acceptable and predictable safety profile when used at clinically approved doses. Efficacy and subtle differences in potential adverse events may exist between drugs in this class. The only way to appropriately compare products within this drug class is through head-to-head clinical trials and target animal safety studies.10 An important note with this class is individual dogs may have vastly different experiences with individual drugs within the class. Lack of response or loss of efficacy to one should not preclude therapy with another. Buckaroo, an eight-year-old mixed breed from Texas, tried numerous treatment options without relief, including steroids and immunotherapy–until his veterinarian recommended once-daily Janus kinase (JAK) inhibitor therapy. The photos show Buckaroo’s skin before starting on the once-daily JAK therapy, after three weeks of treatment, and after eight weeks of treatment. Photo courtesy Elanco Cyclosporine is FDA-approved for the control of canine atopic dermatitis in dogs. Its mechanism of action is primarily mediated via inhibition of T-lymphocyte populations. The medication’s broader anti-inflammatory effects may benefit different clinical presentations of atopy. When effective, cyclosporine administration may be tapered, leading to decreased treatment costs. The full efficacy of the medication may not be appreciated for up to six weeks. Adverse events with therapy are common and most often associated with gastrointestinal upset. Monotherapy therapy with cyclosporine should be considered prior to off-label usage of other products or combining lokivetmab with Janus kinase inhibitors. Corticosteroids remain a mainstay of therapy for canine atopy due to their rapid and predictable symptomatic relief. Unlike newer drugs with more targeted therapeutic effects, steroids have a generalized mechanism of action affecting a greater number of pathways that result in greater potential for adverse events. When used, oral formulations are preferred. Responsible use of steroids involves using them in acute instances, when other therapies have failed, or by providing a spectrum of care considerations.8 When used as a management strategy, they should always be combined with supportive options as a method to decrease the overall required dose. Be cognizant of your clients It probably does not surprise most veterinary medicine professionals that clients of atopic dogs believe the disease affects their dog’s quality of life. However, recent updates surrounding client engagement and caregiver burden are quite eye-opening. Surveys of atopic dog owners have shown roughly half of them believe their dog’s disease is impacting their own quality life.11 Surveys investigating caregiver burden amongst allergic dog owners have suggested they prefer simple and effective treatment that gets their dog’s disease into clinical remission.12,13 From a recent nationwide survey, 60 percent of dog owners say they will lose trust in their veterinarian if they are unable to control their dog’s pruritus, with 80 percent of owners saying they would seek a second opinion.1 In the same survey, five in 10 dog owners indicate they would be willing to move to a new city if it would help their dog’s extreme itching, and 60 percent say they would travel outside their state to see a specialist if it meant their dog’s allergic disease could be put into clinical remission. These findings suggest the simplest client-approved option should be initiated and then changed over time to manage a specific patient as best as possible. Conclusions Atopy is a chronic progressive disease that affects many dogs. The burden the condition places on clients is high, and they are searching for simple, effective, and affordable options that achieve clinical remission. Approaching these cases in a mutualistic manner while understanding your clients’ desires and limitations is key to achieving real therapeutic success with patients suffering with atopic dermatitis. Darren Berger, DVM, DACVD, has extensive experience in clinical practice, research, and education. He worked as a general practitioner and emergency veterinarian in Des Moines, Iowa, prior to completing a private practice dermatology residency in Phoenix, Ariz. Dr. Berger has previously served as a consultant for several animal health companies. He is an author and editor and was previously a tenured professor who taught at several veterinary schools. Berger has special interests in clinical pharmacology and the management of allergic skin diseases. References Elanco Animal Health. Data on File. Hensel P, et al. Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification. BMC Veterinary Research, 2015; 11:196. 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 Veterinary Research, 2019; 15:140. Mueller RS, Olivry T. Critically appraised topic on adverse food reactions of companion animals (6): prevalence of noncutaneous manifestations of adverse food reactions in dogs and cats. BMC Veterinary Research, 2018; 14:341. Mueller RS, Olivry T. Critically appraised topic on adverse food reactions of companion animals (4): can we diagnose adverse food reactions in dogs and cats with in vivo or in vitro tests? BMC Veterinary Research, 2017; 13:275. Olivry T, et al. Critically appraised topic on adverse food reactions of companion animals (1): duration of elimination diets. BMC Veterinary Research, 2015; 11:225. Favrot C, et al. The usefulness of short-course prednisolone during the initial phase of an elimination diet trial in dogs with food-induced atopic dermatitis. Vet Dermatol, 2019; 30: 498-e149. Miller J, et al. 2023 AAHA Management of Allergic Skin Diseases in Dogs and Cats Guidelines. J Am Anim Hosp Assoc 2023, 59: 255-284. Souza CP, et al. A retrospective analysis of the use of lokivetmab in the management of allergic pruritus in a referral population of 135 dogs in the western USA. Vet Dermatol, 2018; 29: 489-e164. Forster S, et al. 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; 36:165–176. Linek M, Favrot C. Impact of canine atopic dermatitis on the health-related quality of life of affected dogs and quality of life of their owners. Vet Dermatol, 2010; 21: 456-462. Spitznagel MB, et al. Treatment complexity and caregiver burden are linked in owners of dogs with allergic/atopic dermatitis. Vet Dermatol, 2021; 32: 192-e50. Spitznagel MB, et al. Assessment of owner perceptions of caregiver burden, veterinarian-client relationship and satisfaction with the provider in canine pruritus: An experimental vignette study. Vet Dermatol, 2024; 35: 81-91. Moyaert H, et al. A blinded, randomized clinical trial evaluating the efficacy and safety of lokivetmab compared to ciclosporin in client-owned dogs with atopic dermatitis. Vet Dermatol, 2017; 28: 593-e145. Fennis EEM, et al. Efficacy of subcutaneous allergen immunotherapy in atopic dogs: A retrospective study of 664 cases. Vet Dermatol, 2022; 33: 321-e75 Loewenstein C, Mueller RS. A review of allergen-specific immunotherapy in human and veterinary medicine. Vet Dermatol, 2009; 20: 84-98.
