Long-term allergy medications
There are two main reasons to treat your dog with allergy medications: he is excessively itchy, and/or he is suffering from recurrent ear or skin infections. Some dogs only need intermittent or seasonal management of their allergies, while patients that are affected year-round usually benefit from long-term, maintenance medications. This is because allergies are a chronic, life-long condition for many of our pets. Indeed, for many pets, their allergies get worse as they age and develop reactions to more allergens.
Allergic inflammation of the skin causes skin and ear infections. When your dog is exposed to something he is allergic to, his skin can become inflamed. This inflammation changes the microhabitat of the skin, from one that is naturally inhospitable to bacteria and yeast, to one that is moist and humid, in which the normal flora bacteria and yeast can proliferate out of control and cause infection.
Therefore, when considering what allergy medication is right for a particular pet, we need to attempt to identify whether the patient is primarily itchy (but doesn’t get many infections), primarily inflamed (suffering from recurrent skin and ear infections), or both.
By categorizing our patients into categories of 1) primarily itchy, 2) primarily inflamed, and 3) both, we can help sort out what allergy medication would be the best starting place for your dog. This is because our three allergy medications that are intended for long-term use in dogs—Atopica, Apoquel, and Cytopoint—also can be divided into these three main categories in regard to what symptoms they best target.
Cytopoint
Cytopoint (lokivetmab) is for those patients who are itchy but don’t get infections. This is due to how Cytopoint works. Cytopoint is a monoclonal antibody to an itch signal called Interleukin-31. After it is injected into the patient, this antibody binds this itch signal in the blood, thereby interfering in the signaling of itch. Cytopoint has minimal anti-inflammatory properties, so it’s common for patients with inflammatory allergies to still get ear and skin infections despite Cytopoint.
Cytopoint is an extremely targeted medication, so it does not affect the overall immune system, and it is not processed by the liver and kidneys, so it is a good choice for patients with other systemic diseases such as liver and kidney diseases. Side effects are exceedingly rare. If helpful, Cytopoint generally should be repeated once monthly during the patient’s allergy seasons.
Apoquel
Apoquel (oclacitinib) is the in-between drug—it has some anti-inflammatory properties, and it is great anti-itch medication. It is a great treatment option for dogs who are both itchy and get some ear and skin infections. Apoquel works very quickly, with benefit often noted the very first day of treatment, and it is well-tolerated medication for most patients, with lethargy and upset stomach relatively uncommon. Because it is processed by the liver and kidneys, I recommend monitoring bloodwork every 6 months to make sure that the patient’s organs are tolerating it well.
Apoquel is a janus kinase inhibitor. This is a class of medications that modulates the inflammatory response. A relatively new medication (on the market since 2013), Apoquel’s long-term safety is becoming more and more established. Because it modulates the immune system, dermatologists have had concerns about whether it could inadvertently suppress the immune system, making our patients more vulnerable to infection or cancer. Fortunately, we now know that, at the therapeutic dose range, there is minimal increased risk of atypical infections, and patients have the same overall risk of developing cancer as patients not on Apoquel.
Atopica
Atopica (cyclosporine) is our best anti-inflammatory medication intended for long-term treatment of canine skin allergies. It is the treatment of choice for patients with unrelenting chronic ear or skin infections, or for patients with unique inflammatory allergy manifestations, such as interdigital folliculitis/furunculosis (occasionally referred to as interdigital cysts), which are caused by inflamed, exploded hair follicles in between the toes.
Atopica is a calcineurin inhibitor, a family of medications that target inflammatory pathways in the body. Its effects on the immune system vary with dosage. At the dosage of Atopica used to treat skin allergies, the effect is anti-inflammatory and not generally immunosuppressive.
Atopica can be an annoying medication that requires some artful handling to successfully prescribe the medication. It is slow to take effect, and it can be hard on the stomach when initially prescribed. However, proactive strategies can help the patient initially tolerate it. Then it can be slowly tapered to the lowest effective dosage.
Because Atopica is an old medication, and because it’s used in human medicine, generics are available to save cost. Its age also means that its various foibles and long-term safety are very well established. At the allergy dosage, there is minimal risk minimal increased risk of atypical infections, and patients have the same overall risk of developing cancer as patients not on Atopica.
Other treatment options
There are two other families of medications used to treat canine allergies: anti-histamines and steroids such as prednisone.
- Anti-histamines are statistically as effective as placebo (sugar pills)—about 10% of dogs improve with these medications. So, while they have excellent safety, they are often simply not helpful as solo medications. We might find that they are more helpful when added into the more potent medications mentioned above.
- Steroids, on the other hand, are extremely effective for allergic dermatitis, but they are not very safe for long-term use. We generally recommend our 3 medications intended for long-term treatment of allergies, Atopica, Apoquel, and Cytopoint, if we see that patients are requiring multiple courses of prednisone to manage their allergies.
Allergen specific immunotherapy (ASIT)
While allergy medications work relatively quickly to treat the clinical signs of dogs’ allergies, they don’t alter the course of disease. If the allergy medications are discontinued, the allergy symptoms will recur. However, there is a treatment option that aims to treat the underlying cause of the allergies. Allergen specific immunotherapy (ASIT) is the only therapy that can potentially alter the course of the disease by making the patient potentially less allergic to their particular allergens.
To formulate ASIT, we must first perform allergy testing to identify major allergens. Then, those specific allergens are made into ASIT, a tailored preparation for that particular patient. ASIT is given either as injections at home or the vet (subcutaneous immunotherapy or SCIT), or orally (sublingual immunotherapy or SLIT).
The goal is to slowly build tolerance to the allergens so that, with time, the patient learns to ignore the allergens or mount less severe of an allergic reaction. Immunotherapy is effective in about 70% of patients at reducing or eliminating the need for medications.
Immunotherapy takes about 1 year to help most patients. Because there is a lag until the immunotherapy takes effect, we manage our patients with allergy medications while the immunotherapy builds in the system, and then we aim to slowly taper the allergy medications with time.
While we can simply be patient and slowly allow the immunotherapy to build in the system, following traditional immunotherapy protocols, there are induction protocols that can speed up the process. An example of an accelerated immunotherapy induction is RUSH immunotherapy, which is offered by our hospital. Animals undergoing a RUSH procedure spend one day with us, from 8:30 am-4:30 pm, during which the first several months of immunotherapy are administered under close supervision. This procedure, which—though sounding quite exciting/risky, is actually quite safe—simply speeds up the onset of immunotherapy, and it allows for the patient to go home needing fewer injections per month. In patients that successfully respond to immunotherapy, immunotherapy is generally continued long-term; discontinuing immunotherapy risks eventual relapse and recurrence of the allergic skin disease.
