A One Health approach to allergy treatment

Recommend diagnostic testing as dictated by clinical signs and level of suspicion and explain to clients its value to help increase compliance and improve response rates.

Small animal veterinarians know managing allergies can be our bread and butter while also causing pangs, headaches, frustrations, and challenges. Ensuring we select appropriate therapies to manage dermatological manifestations of allergies (and other skin conditions) requires us to do so through a One Health lens. Our decision process must include environmental concerns and human and pet health interests.

Practicing proper antimicrobial stewardship, knowing when to reach for topicals vs. oral therapies, and including owners in decision-making can improve healthcare outcomes and strengthen and nurture the human-animal bond.

Allergy management strategies

Twenty years ago, our go-to management for skin infections and allergy management was very limited. Topical therapies were in existence but not readily reached for, and oral antimicrobials were usually the first grabbed off the shelves. Fast forward to 2024, and we have seen evidence-based medicine and recommendations by veterinary experts emphasize the need to consider reaching for topicals first and, whenever possible, limiting our use of oral antimicrobials.

Today, we have an ever-improving arsenal for treating and managing allergic diseases in our animals. From topical shampoos, sprays, creams, and moisturizers to medicated wipes, leave-in ear medications, oral antimicrobials, steroids, to anti-itch medications from antihistamines, to biologics, to allergy immunotherapy, to hypoallergenic diets. With this selection comes responsibility to our profession, patients, pet parents, and ourselves to ensure the safest choice for individual animals, with the least damaging impact on the patient, human-animal bond, and the environment.

To test or not to test

The ideal standard of care would be diagnostics for every patient regardless of cost and ability to pay. While this, sadly, cannot happen 100 percent of the time in veterinary medicine, we still need to recommend diagnostics, including skin scraping, skin cytology, ear cytology, trichograms, ringworm testing, and other options as dictated by clinical signs and index of suspicion. Not only should we recommend these tests when appropriate, but we need to ensure we explain to clients the value. You can say: “Mrs. Smith, ear cytology helps me determine the severity of the infection and whether yeast, bacteria, or both are contributing to signs. After treating the infection, rechecking the cytology will show if we succeeded. While your pet may not be shaking his head or scratching his ears, and the discharge may appear gone, we must look to confirm. If we fail to do so, signs will return, and medication resistance may develop. While I understand your cost concerns, I wanted you to realize the test’s value.”

By explaining the benefit and how it can guide treatment, reduce overall costs (by treating appropriately the first time), and permit evaluation of clinical resolution, we can improve response rates and have happier clients.

Treating infections

Treatment options come in many shapes and sizes. We must consider our client’s ability to comply with any recommendations, therapy side effects, and ease of administration or application of selected treatments.

Topical management. This equates to our first line of defense and should be our go-to.1 However, while evidence suggests topical is our best offense for superficial infections and many related skin conditions, we must consider our client’s ability to follow any treatment protocol we prescribe. Is the owner an 80-year-old woman who cannot physically bathe her 75-lb, mixed-breed dog? Is the dog petrified of the bathtub? Can the owner touch the dog’s ears?

Oral therapies. These include anti-pruritic medications, steroids, antimicrobials, and even immunosuppressive (e.g. cyclosporine) therapies, which depend on the underlying condition, disease severity and duration, and patient and owner needs and expectations. These may be required for deep pyodermas or when topical medications fail. Further, when owners cannot apply topical therapies due to physical inabilities or patient disposition.

Not all skin conditions and patients present with actual infections. Sometimes, seborrhea sicca or olea are the only clinical concerns. Sometimes, pruritus presents without infection because of underlying atopy or food allergies. Addressing the underlying cause, infection or not, is paramount.

Ideally, therapy is guided by cytology at a minimum when infection is present. If you have a patient you feel needs oral therapy, or owners cannot use topical or topicals that have failed to resolve the issue, orals may be warranted. However, it is not as simple as reaching for whatever antimicrobial fits your patient’s weight range based on standard dosing.

A veterinarian talking to a client.
It is crucial to stress to clients the importance of maintenance and preventive care for minimizing infection risks, discomfort, and the development of resistant organisms to help promote overall pet health and well-being.

Antimicrobial stewardship

When considering therapy selection, veterinarians should strive to practice proper antimicrobial stewardship. We must think about possible future ramifications for the individual animal, future animals, human health, and the environment, a true One Health perspective when deciding on what to choose.

Antimicrobial stewardship refers to key actions veterinarians, individually and collectively, need to utilize to “preserve the effectiveness and availability of antimicrobial drugs through conscientious oversight and responsible medical decision-making while safeguarding animal, public, and environmental health.”2 As part of practicing proper antimicrobial stewardship, the American Veterinary Medical Association (AVMA) states we must “select and use antimicrobial drugs judiciously.”2,3

When practicing proper antimicrobial stewardship, you want to reach for the narrowest spectrum you know will appropriately treat the skin. You do not want to grab the big guns right out of the gate. The World Small Animal Veterinary Association (WSAVA) has numerous guidelines and documents that can be very beneficial for dermatological, respiratory, and other conditions and help guide you on using antimicrobials responsibly and preventing antimicrobial resistance (AMR).4

Do your best to reserve second and third-tier medications for resistant infections or patients that fail to respond to a first-line medication.5 By selecting an appropriate antimicrobial for the degree and type of infection while keeping in mind reserving the bigger guns for resistant infections and preserving various drug classes for human use, we lessen any potential damage to the pet’s GI microbiome while minimizing the risk of AMR in individual animals and their environment.

Further, consider the duration of therapy. Stewardship includes using these medications for the shortest duration possible to achieve clinical resolution. We do not want to use antimicrobials for longer than necessary. Research is ongoing about the treatment duration required. Currently, we treat for one week beyond clinical resolution for superficial infections. However, this is where the recheck becomes even more valuable. We can re-evaluate the patient, and if the infection has cleared, why keep the patient on medications? Sometimes, these medications cause side effects and potential damage to the GI microbiome while potentially increasing the risk of AMR with every dose.6

Managing the dreaded itch

Thankfully, we have several options in pruritus management in our current arsenal. However, as responsible veterinarians, we must advise clients of the various options, possible side effects, possible benefits, duration of action, time until they take effect, and related information. Failing to do so affects compliance and overall patient health and safety.

Choices for managing itch, irrespective of the presence of infection, include numerous options in addition to treating any underlying infections and, ultimately, managing the fundamental trigger, be it atopy, food allergy, or other etiology.

Varying levels of evidence exist for numerous remedies to ail itching and treat atopy and related conditions in dogs and cats. Always be sure you are current on the evidence to date and are familiar with when and how to use these options safely and effectively. Options include:7-18

  • Corticosteroids. Despite significant side effects, these drugs have a place in allergy management. However, owners must be properly informed of both short-term and long-term use effects. They need to understand abruptly stopping this type of medication is not appropriate and, ideally, we hope to avoid using them for long-term use.
  • Biologicals (monoclonal antibodies or mABs). lokivetmab
  • Janus Kinase inhibitor-1 (JAK). oclacitinib
  • Allergy “shots” or sublingual allergy immunotherapy
  • Antihistamines. Efficacy studies in animals in controlling pruritus associated with pyodermas and atopy show minimal improvement, often 15 percent or less. Owners need to be advised of this. One caveat to this would be the use of diphenhydramine in acute allergic reactions.
  • Treating the underlying disease. For example, with flea allergy dermatitis, treat the fleas and any secondary infections; for atopy, consider allergen immunotherapy and hypoallergenic food trials. We all know the itch will never fully resolve, but we can control it better if we address the deep-rooted cause.

    NUTRACEUTICALS: BENEFICIAL OR PLACEBO?

    Some veterinarians may recommend using omega fatty acids (some evidence to support use) or other nutraceuticals to adjunctly manage dermatological conditions. However, because of a paucity of significant data supporting the beneficial use of these nutraceuticals, most dermatologists do not recommend most of these products. Most current research assesses nutraceuticals as adjuncts with conventional therapy rather than standalone treatments.19

    One exception may be the use of probiotics. With increased attention being paid to microbiome health (the body’s natural flora including the skin and GI tracts), the role it plays in the overall health of an individual animal, and the negative effects that dysbiosis can have on numerous bodily functions and overall state of health, probiotics may be recommended. Those with scientific studies to support their benefit may be warranted, especially in individuals with atopic dermatitis.20,21

Our duty to caution of side effects

As a veterinarian, we are responsible for advising clients of any side effects to any medication treatment protocol, as well as the risks of not treating, failing to treat for the appropriate duration, failing to complete a course of topical or oral therapy and risks of recurrence.

While leave-in ear medications ease owner angst about treating otitis and improve the human-animal bond (no ear cleaning and daily med administration needed), any ear medication can potentially cause damage to the ear drums. If we select a leave-in medication, it is our duty to advise the client, before application, that it is a potential, though uncommon, risk.22,23

Antibiotics and other oral medications can cause GI side effects and even negatively impact the health of a pet’s natural GI flora (microbiome health). Steroids can lead to frustrating increases in urination, drinking, and appetite while causing some animals to become agitated and dogs to pant more than normal. Failing to advise owners of these signs and not having them contact you if concerned can do harm, something we took an oath to prevent when at all possible.24

Rechecks: yay or nay?

Ideally, all infections should be rechecked. We want to ensure the treatment worked, that the owner is happy with the results, that the patient no longer has clinical signs, and that success is assured. To owners, it is paramount to emphasize the importance of recheck evaluations, including diagnostics, when warranted. We all know that allergies, atopy, and most skin conditions are managed, not cured. Owners need to understand that while we may treat an acute infection and resolve that completely, the underlying inciting cause, ectoparasites, environmental allergies, food allergies, genetic predisposition, or a combination thereof, needs to be managed but cannot be forever obliterated.

Emphasizing to owners the importance of maintenance and prevention strategies to help lessen the risk of recurrence or of new infections, minimize patient discomfort, improve the global quality of life (for pet and pet parent), and prevent the development of resistant organisms is crucial to the pet’s overall health and well-being.

Being stewards for One Health

We all have our favorite product brands, first choices for shampoos, sprays, oral antimicrobials, and standard treatment protocols for superficial dermatitis and other common allergic disease manifestations in our small animal patients. However, perhaps we could all use a bit of a bigger-picture view. Step back and evaluate your overall plan with each animal and owner in mind.

Consider the pet parent’s goals and abilities to comply with management and prevention recommendations. Consider ease of administration, duration of treatment needed, recheck evaluations, and reach for topicals before orals whenever possible. This helps spare the GI tract, protects the microbiome, and lessens the risk of developing AMR. This enables us to ensure proper antimicrobial stewardship practices, protecting our patients, human health, and ultimately, the environment, a One Health practice.

Erica Tramuta-Drobnis, VMD, veterinarian, CPH, is the CEO and founder of ELTD One Health Consulting, LLC. Dr. Tramuta-Drobnis works as a public health professional, emergency veterinarian, freelance writer, consultant, and researcher. She is passionate about One Health issues and believes pet health, food safety, agricultural health, and more can address the interconnection of human, animal, and environmental health.

References

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