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Atopic dermatitis

Photo from Pixabay

By Matthew Kearns, DVM

My last article focused on the older treatments for atopic dermatitis with some of the treatments largely ineffective in more severe cases and, others, having too many adverse side effects. Very briefly, atopic dermatitis in pets is defined as, “a chronic, itchy, inflammatory skin condition that occurs in genetically predisposed animals,” or a rash associated with seasonal allergies. Here are some of the newer medications available for the treatment of atopic dermatitis.

Cyclosporine (Atopica®): cyclosporine is classified as an immunosuppressant but, overall, it is much safer than corticosteroids (cortisone derivatives) long term for the use of treating chronic atopic dermatitis. Cyclosporine prevents the activation of a certain type of white blood cell called T cells and the inhibition of certain chemicals called interleukins, as well as others. The main side effect is gastrointestinal (nausea, vomiting, diarrhea, flatulence). Cyclosporine has also been linked to increased risk of certain types of neoplasia (tumors, cancer) in certain breeds. 

Oclacitinib (Apoquel®): oclancitinib is classified as a novel, selective immunosuppressant. Oclancitinib inhibits the enzyme janus kinase. Janus kinase acts as a signal for the immune system to attract cytokines, or mediators of inflammation. Specifically, oclancitinib inhibits a type of cytokine called interleukins. The interleukins inhibited are pro-inflammatory. There is a benefit to inflammation in immune responses to fight diseases however, the interleukins inhibited are responsible for itching and rashes associated with atopic dermatitis. At least 60% of dogs have responded with a substantial decrease in itching and rashes when oclancitinib is used long term.

Lokivetmab (Cytopoint®): lokivetmab is classified as an anti-canine IL31 monoclonal antibody, but technically lokivetmab is an allergy vaccine. “IL31” is short for interleukin-31. Interleukin-31 is a cytokine that specifically triggers pruritis, or itching in the brain. Injecting itchy dogs with lokivetmab, or antibodies against IL31 reduces itching in over 50% of dogs treated. Unfortunately, lokivetmab is not effective in preventing the rashes and skin infections. Therefore, secondary treatments (antibiotics, antifungals, medicated shampoos or sprays, etc) may be required to manage atopic dermatitis in some patients.

Allergy Specific Immunotherapy (ASIT): this refers to testing for what a patient is allergic to and attempting to desensitize them to those allergens. The testing can be either: serum (blood), or intradermal. Many veterinarians will be able to draw the blood needed to send out for testing. Intradermal testing is usually done under the guidance of a veterinary dermatologist. Testing should include both food and environmental allergens. This way we can avoid certain diets that would definitely cause a reaction, as well as desensitize the body to known environmental allergens with a customized injection or sublingual (under the tongue) drops. Both are quite effective. 

I have found that some cases require short courses of some of the old school medications for “flare ups” at certain times of the year even if they are doing well on the new school treatments for most of the year. As always, check with your own veterinarian as to which treatment is best for your pet. 

Dr. Kearns practices veterinary medicine from his Port Jefferson office and is pictured with his son Matthew and his dog Jasmine. 

METRO photo

By Matthew Kearns, DVM

The weather is changing and I’m getting more itchy patients coming to my office. Owners describe scratching and rashes appearing seemingly out of nowhere and they want relief for their pets. I explain to these owners that their pet most likely suffers from atopic dermatitis. 

Now, before I discuss treatment options for atopic dermatitis, we need to clearly define what it is. Atopic dermatitis in pets is defined as “a chronic, itchy, inflammatory skin condition that occurs in genetically predisposed animals.” 

What triggers this chronic condition? Pollens, mold spores, dander, dust mites, etc. Basically, atopic dermatitis equals seasonal allergies in pets. There are more choices in treatment these days and I would like to briefly go through the options.

Omega-3 Fatty Acids:  Omega-3 fatty acids are actually classified as supplements. However, they can be effective in controlling less severe cases of atopic dermatitis, or in conjunction with actual medications. The source of the highest levels are cold water fish so fish oil capsules or fish-based diets are recommended. There are also topical formulations of fatty acids that are applied directly to the skin. These oils prevent pro-inflammatory chemicals the body produces such as prostaglandins and leukotrienes. 

Omega-3 fatty acids are very safe because they are supplements but, in my experience, are rarely effective alone in treating atopic dermatitis. They work better in conjunction with some form of medication. 

Antihistamines: Histamine is a chemical produced by the body which, in small amounts, has a beneficial effect on the body. Histamine plays a role in normal cell metabolism. However, atopic patients produce larger amounts of histamine and larger concentrations of histamine in the body causes inflammation and terrible itching. Antihistamines block the histamine receptors on cells. These medications are very safe, readily available over the counter, and inexpensive. Unfortunately, they are in my opinion, very variable in their effectiveness and the least effective compared to the other choices.

Corticosteroids (cortisone derivatives): Corticosteroids include medications like dexamethasone, betamethasone, prednisone, isoflupredone, etc. These corticosteroids of different names vary in strength and half-life, or how long it takes to clear the system. These are very powerful medications and this means two things: 1) they are the most consistently effective medications in controlling the itch of allergies, and 2) they have a lot of side effects. 

The most common benign side effect is drinking and urinating more. Increased appetite and panting are also common. However, when corticosteroids are used short term for what are considered “flare ups,” the medication is generally considered quite safe. However, when used long term even at low doses, the detriment of adverse effects outweighs the benefit of the medications. These adverse effects include diabetes, pancreatitis, a suppressed immune system, stomach and intestinal ulcers, organ dysfunction, etc (this is not a complete list). 

Corticosteroids do have their place in treating what are called “flares” or acute, severe dermatitis short term in conjunction with a safer, long term treatment.

In my next article I will discuss some of the newer options used in the treatment of atopic dermatitis. As always, consult with your own veterinarian before choosing any treatments or medications.

Dr. Kearns practices veterinary medicine from his Port Jefferson office and is pictured with his son Matthew and his dog Jasmine. 

If it wasn’t for the side effects, corticosteroids would be a magic bullet. Stock photo
Getting to the source of the itch

By Matthew Kearns, DVM

My last column introduced the seasonal allergies that our pets can suffer from, also known as atopic dermatitis. This second part of the two-part article focuses more on the treatment of atopic dermatitis. The treatments we will discuss only focus on systemic medications. It does not include supplements, topical creams/powders/sprays, medicated shampoos/conditioners, etc. I’ll make sure to cover that in the future. 

Now, if we remember from the first part of the article, atopy is defined as, “a genetic predisposition to develop a sensitivity to allergens (proteins in the environment).” The body develops antibodies against these allergens (primarily IgE) and, once a threshold is reached, the IgE antibodies trigger signals to certain white blood cells called basophils and mast cells to release inflammatory chemicals into the system (primarily histamine). This release of histamine triggers all the itch and secondary skin and ear infections that frustrate both pet owners and veterinarians. What is out there to help with the problem?


Antihistamines block the histamine receptors on nerves, vessels, muscle cells and the lining of stomach and small intestine. They are readily available without a prescription and safe so they can be an excellent first choice. Unfortunately, antihistamines do not block the release of histamine from basophils and mast cells but rather block the receptors on the cells of the organs they affect.  

Now, you can’t block every receptor with medication so it very much depends how severely the individual pet responds to an atopic, or allergic, reaction. Pets with mild allergies will do well with antihistamines. However, pets with more severe forms of allergies either do not respond well or respond temporarily to antihistamines and eventually need a stronger medication.


Corticosteroids, glucocorticoids, or “steroids,” as they are sometimes referred to, are all cortisone derivatives. Systemic cortisone medications are prescription only. However, corticosteroids are inexpensive and very effective at treating atopic diseases. They block the production of all cytokines (mediators of inflammation) and, if it wasn’t for the side effects, would be a magic bullet. Short-term use is relatively safe and very beneficial. Side effects include drinking/urinating more, eating more and panting. 

However, long-term side effects include gastrointestinal upset/possible ulcers, a suppressed immune system, diabetes mellitus, liver damage, pancreatitis, thromboemboli (blood clots), increased risk of urinary and other types of infections, lethargy and, sometimes, aggression. 

We, as veterinarians, try to transition patients with chronic, recurrent skin and ear problems to other, safer long-term medications.


These prescription medications are more effective than antihistamines and safer to use long term than corticosteroids. Medications like Atopica (cyclosporine) and Apoquel (oclacitinib) block a specific receptor and prevent specific cytokines associated with the allergic itch. These are newer medications with minimal side effects and safe to use long term but are more expensive than antihistamines or corticosteroids.

Biologic therapy 

This is the newest kid on the block. Biologic therapy uses the body’s immune system to target cytokines, or chemicals that induce inflammation. Cytopoint (lokivetmab) is a once monthly injection that induces your dog’s immune system to produce antibodies against a specific class of cytokines called interleukins. Interleukins have been linked to the itch in allergic or atopic dermatitis.

Multiple factors play into what medication we choose: severity, age of pet, pre-existing disease and cost of medication. I hope pet owners will start the discussion with their own vet as to which medication is best for their pet.  

Dr. Kearns practices veterinary medicine from his Port Jefferson office and is pictured with his son Matthew and his dog Jasmine.

Allergens are classified into four major categories in veterinary medicine: pollens, mold spores, dander and dust mites. Stock photo
Getting to the source of the itch

By Matthew Kearns, DVM

I expect at some point there will no longer be any snow on the ground. Once that happens I will truly suffer with burning eyes, runny nose, sore throat and an intermittent cough. Ugh, my wretched seasonal allergies are back!! 

Well, just like us, pets can also suffer from seasonal allergies. Pets can suffer from all of the signs I mentioned above but, most commonly, they suffer from itchy feet, recurrent ear infections and rashes all over the body. 

This phenomenon of seasonal allergies is known as atopy, or atopic dermatitis. Dermatitis stands for “inflammation of the skin,” or a rash. Atopy is defined as “a genetic predisposition to develop allergies to allergens” (proteins in the environment). Atopy and atopic dermatitis hiccup in the immune system. 

The immune system produces immunoglobulins (Ig), or antibodies, to protect us against infections and parasites. There are five major classes of immunoglobulins: IgA, IgD, IgE, IgG and IgM. These antibodies work with white blood cells to trigger the release of cytokines. Cytokines are chemicals that fight against/kill bacteria, viruses, fungal infections, parasites and even cancer cells. The antibody IgE is the antibody associated with allergies. IgE has a beneficial effect by protecting against certain parasites, particularly gut parasites. 

Unfortunately, these same IgE antibodies recognize allergens, or proteins associated with allergies, the same as parasites. This fools the immune system into producing more IgE antibodies that trigger a certain white blood cell called basophils into releasing large amounts of cytokines (particularly histamine) into the system. This release of histamine causes a systemic reaction that triggers inflammation of the skin all over the body. 

Allergens are classified into four major categories in veterinary medicine: pollens, mold spores, dander and dust mites. Each of these allergens is going to be in higher concentrations at different times of the year. Pollens are high when grasses, weeds, flowers and trees bloom, which is late spring/early summer through late fall. Mold spores are from decaying plant material and occur from late fall/early winter and late winter/early spring. Dander and dust mites are around in the cold winter with low humidity.  

We mentioned at the beginning of the article that pets can suffer from all the same symptoms of hay fever, but it is less common than skin rashes and ear infections. Why is that? Those same allergens that are in the air also land on the ground, and research has found pets that suffer from atopic dermatitis are triggered by percutaneous (through the skin) absorption. 

These pets have defects in the lining of their skin so the allergens are literally absorbed through their feet and other areas where the skin is exposed (stomach, face). Many times if we see pets that have a severe pododermatitis (inflammation and infection of the skin on the feet) that is a clue that atopy or a seasonal allergy is afoot (no pun intended). Once we diagnosis atopic dermatitis we next need to treat it. We will discuss how to treat this condition in my next article.

Dr. Kearns practices veterinary medicine from his Port Jefferson office and is pictured with his son Matthew and his dog Jasmine.