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The Itching Pet: Alternatives to Steroids
Excessive licking, chewing, and scratching can make a pet’s life miserable for month after month, even year after year. No one likes to see their pet uncomfortable; furthermore, the constant licking, chewing, and scratching can keep a pet owner up at night from the noise. Clearly, uncontrolled itching is a problem to solve before it gets out of hand.
Siamese cat on deck
Photo courtesy Depositphotos
For reliable rapid relief of itch and inflammation, it is hard to match the corticosteroid hormones such as hydrocortisone, triamcinolone, methylprednisolone, prednisone, dexamethasone, and others. There are some animals that seem unable to live with any degree of comfort without these medications. Unfortunately, these hormones have widespread and potentially dangerous actions throughout the body when they are used for inappropriately long periods and it is generally desirable to minimize the use of these hormones when possible to do so. Ideally, corticosteroids are used for a few really tough itch weeks and other forms of itch management are used for general itch maintenance.
Of course, this is easier to write about than to actually do. When your pet is scratching and chewing raw spots on his skin, practical advice is what is called for. The following list includes assorted non-steroidal methods for relieving itch and reducing the amount of corticosteroid hormones needed.
Staphylococcus bacteria is the main target of cefpodoxime. Photo courtesy of CDC
When an animal becomes suddenly itchier, we tend to assume there must have been a new or sudden allergen exposure. While this is possible, most of the time what has actually happened is an infection has taken root in the skin as a result of scratching and chewing. In many cases, controlling the infection will bring the pet back into its comfort zone and many allergic animals are managed by simply having their infections treated when they flare up.
The usual infections involve the Staphylococci bacteria and/or the Malassezia fungi that normally live on the skin surface. When the environment of the skin changes (allergic skin loses water and may have more oils), these organisms multiply and can gain access to deeper layers of the skin through abrasions caused by scratching and chewing. Soon there is a rash and/or an odor. Antibiotics generally handle these infections, though sometimes culture is necessary to determine what antibiotic is needed. Expect an itchy animal to have some skin samples reviewed under the microscope to check for infection. Some itchy pets need continuous management for these infections while, as mentioned, others only need periodic treatment. Ideally, additional treatments are used between infection flare ups to extend the time between them.
Lokivetmab (Cytopoint®, Canine Atopic Dermatitis Immunotherapeutic, Cadi)
A relatively new product is lokivetmab, a monoclonal antibody genetically engineered to target the canine version of a biochemical called interleukin 31. Interleukin 31 is a type of cytokine and is an important mediator of itching so when it is inactivated by antibodies, relief from itch is rapidly achieved (usually beginning 8 hours after injection and readily apparent after 1 day). For over 80% of dogs receiving the injection, results are sustained for at least 4 weeks. That said, it does not work for every dog, and while some dogs experience more than 4 weeks of relief, others experience less.
Lokivetmab does not affect pre-existing infections other than to make them not be itchy. It only provides symptomatic relief, but for many itchy dogs, stopping the itch/scratch cycle is needed to curtail the vicious cycle and stop the perpetuation of skin infections. This product is excellent at extending the interval between skin infection flare ups.
Antihistamine and Antihistamine Trials
Histamine, a biological chemical, is the chief mediator of inflammation in humans, hence the proliferation of antihistamines available for people both by prescription and over the counter. Histamine is not the major mediator of inflammation in dogs, thus these medications are not as reliable for dogs as they are for us.
The International Committee on Allergic Diseases in Animals puts out guidelines for managing atopic dermatitis, and they divide itch into acute flare ups and more chronic daily levels of itching. They found little benefit from antihistamines for acute flare ups except for mild cases and consider that the drowsiness side effect may be responsible for any reduction in scratching. For more chronic cases, daily use of antihistamines fared better with the idea that regular use might be preventing flare ups even if antihistamines were not so good at actually treating flare ups. Responses were variable between individuals.
While the chance of any one antihistamine being effective is small (about 15% on the average), trying several antihistamines sequentially often leads to finding one that works. It is important to note that many antihistamines have a drowsiness side effect. Antihistamines commonly used for such trials include:
Cyclosporine is an immuno-modulating drug originally developed for use in organ transplant patients but also useful in other immune-mediated diseases. Since allergy is an immune-mediated condition, cyclosporine was investigated as an alternative to corticosteroids and found effective for most patients. A good four to eight weeks are needed to see a good response to cyclosporine which makes it fairly useless for acute flare ups. Typically it is combined with a medication that yields rapid itch relief so that by the time the itch is controlled, the cyclosporine can take over. Cyclosporine tastes bitter and commonly generates a mild upset stomach when it is first used. Cyclosporine is available for both dogs and cats.
This relatively new medication is a new approach to itch relief. Oclacitinib is called a JANUS- kinase inhibitor and it exerts its’ effects in the skin just as rapidly as do corticosteroids. This makes it helpful for both acute flare ups as well as long-term management of itching. It is important to realize that its’ effects seem to be only on the sensation of itching and, unlike steroids, there is no anti-inflammatory result. This means that the patient’s itch can be controlled in the face of even advanced skin infection. This might sound like a good thing but there is concern that if the patient is not itching, the pet owner may not be motivated to perform the therapy needed to control the skin disease. Oclacitinib is approved for dogs but feline use is being explored. Patients should be over age one year and should not have a history of cancer or demodectic mange.
Fatty Acid Supplementation
The discovery of anti-inflammatory properties of evening primrose oils and fish oils in humans has led to similar products on the market for our pets. These products are not analogous to the oil supplements that are recommended to make a pet's coat shiny; instead these are true anti-inflammatory medications capable of relieving joint pain, cramps, and itchy skin.
They are not at all useful for acute flare ups of itching as they require weeks to build up in the body in order to exert an effect. Instead, they are used for long-term management in making the skin less able to generate inflammatory mediators. (Essentially, they make the skin less reactive to allergens).
The supplement alone is mild in its ability to prevent itch but it can be used to boost the effects of other anti-itch medications.
Ultra-Microsized Palmitoylethenolamide or "PEA" (Redonyl®)
PEA is a natural substance made by both plants and animals. In animals, it is involved in restoring balance to the skin's biochemistry and preventing release of the biochemical mediators of itching. (The actual process involves enhancing levels of endogenous endocannabinoids and is fairly complex.) The commercial product uses an extract of soybeans to obtain its PEA and creates a super concentrate as it would not be possible to eat enough soybeans to garner a therapeutic dose of PEA. The super small "ultra micronizing" allows for better absorption of the product. It is available as a flavored chew for dogs and can also be used in cats.
We now know that topical steroids (cortisone crèmes, sprays, and related products) are absorbed through the skin and into the bloodstream, but the systemic hormonal side effects achieved with topical use do seem blunted and probably only of significance for very small dogs. This makes topical steroid use a much safer long-term approach relative to oral or injectable steroids. Of course, the entire animal cannot be enrobed in topical steroid cremes but for small irritated areas (hot spots), topicals can provide excellent relief without the systemic effects of hormones. They are best used for acute flare ups.
Dog in Bathtub
Photo courtesy of Depositphotos
There are many benefits to shampoo therapy: luke warm water is inherently soothing, crusts and dandruff that could be inherently itchy can be removed, pollens and other allergenic substances can be washed away, the skin can be either moisturized or stripped of excess oil depending on what is needed and, of course, medications can be delivered in the shampoo lather itself. Skin can be moisturized with shampoo therapy, which reduces the sensitivity of the skin to itch stimulation. (The itch threshold is raised through skin hydration). As technology advances, new products are introduced and ways to prolong their effects are developed. Here are some general choices that might be helpful:
- Colloidal Oatmeal Shampoos and Creme Rinse - At first, these products were only available for human use, as powdered soaks to pour into bath water. Once their value in itch management was determined, their use quickly spread to the veterinary field. Colloidal oatmeal has an unknown method of action but generally yields one to three days of relief. The creme rinses are meant to yield longer acting relief. They are available plain or combined with local anesthetic formulas (usually pramoxine) to soothe itch.
- Phytosphingosine Containing Products - These products contain phytosphingosine, a natural skin biochemical important in maintaining the skin’s natural barrier to infection and inflammatory substances. Phytosphingosine is moisturizing, anti-inflammatory (both directly and by fortifying the skin’s barrier function), and has antimicrobial properties (preventing and treating bacterial as well as yeast infections). Generics are also on the market as well. The Douxo® line is available in shampoos as well as sprays.
- Lime Sulfur Dip - This product kills parasites, ringworm fungi, and bacteria. It also dries moist, weeping skin lesions and helps dissolve surface skin proteins that are involved in itchiness. Many veterinary dermatologists recommend it regularly to control itch; however, it has several disadvantages. IT SMELLS TERRIBLE. The sulfur ingredient smells like rotten eggs and this is how your bathroom or bathing area will smell during the pet's bath. This dip can stain jewelry and clothing and will temporarily turn white fur yellow.
- Other Shampoos - Itchy skin can be the result of skin infection, excess oil accumulation, yeast infection, even parasitic infection. The list goes on. The shampoo products listed above can be used against any itchy skin disease but it should be noted that there are many other shampoo and creme rinse products that can be used against the specific conditions.
Ten minutes of skin contact is the minimum requirement for any medicated shampoo. Premature rinsing will not allow for the therapeutic benefit to be realized.
Respect the Steroid
Severe itching amounts to a reduction in life quality. It is important not to develop the mindset that corticosteroids should be avoided at all costs. This would not be fair to the itching pet. Steroids are valuable tools in the relief of pain and suffering and have an important place the therapy of the itchy pet.
The goal is not to avoid steroid use if possible but to avoid long term dependence on steroids if possible. Despite all of the above management tricks, some pets will still require long term steroid use to achieve any reasonable comfort. There are monitoring protocols in place for such cases. It should also not be forgotten that underlying allergies and recurring skin infections can be addressed specifically and that as these conditions are managed, the itch is also managed.
Steroid hormones have many side effects and, as helpful as they are for allergic skin diseases, it is best to reserve them for only the most itchy episodes.
A Few Words about Flea Control
We receive email on a daily basis from people with itchy pets who are convinced that fleas are not involved in the problem. When we examine such pets, we find fleas actually are contributing to the itching in at least 50% of cases and the owner is invariably surprised to see the live fleas when they find them. Since any itchy skin disease is made worse by fleas, good flea control is imperative and it is important not to assume that not seeing fleas means they are not there. For example, if your pet’s itchiest areas include the lower back, this is a strong indicator that your pet has fleas whether you see them or not. Often, becoming diligent with flea control is the least expensive and least labor-intensive way to control a pet’s itch symptoms.
VIN News Service commentaries are opinion pieces presenting insights, personal experiences and/or perspectives on topical issues by members of the veterinary community. To submit a commentary for consideration, email email@example.com.