Ultrasound

Sorry about the lack of blogging recently.  With the summer, things have been a little hectic.  I wanted to take some time now to discuss a newer form of testing we have added to our clinics here in Champaign/Urbana.  We have recently started to offer ultrasound services at our clinic in Savoy.  Currently, these are limited to abdominal (stomach, kidney, liver, spleen, etc) imaging, but we hope to offer echocardiogram (heart) imaging in the future.

The question you might be asking is what is ultrasound and when might we need to use it for your pet.  Unlike x-ray, which uses radiation to take images, ultrasound uses sound waves that are directed towards organs and the machine listens for the sound reflections from these organs to make images.  So instead of just being able to evaluate the outline of the liver or intestines (such is done with x-rays), we are able to better evaluate the architecture of organs.

Above are examples of ultrasound images from the intestines of cat.  As you can see, we can observe the different layers of the intestines and effectively evaluate for any thickening of the bowel or possible obstruction.

You might ask what would be a good use for this form of technology?  There are many patients where ultrasound can be helpful.  I will just talk about a couple examples.

Some owners have cats that may vomit periodically or may be losing weight.  We start with blood work and don't find many changes.  The next step may be an abdominal ultrasound.  During the ultrasound we scan all the abdominal organs, but in this case would likely focus on the intestines and pancreas.  With the ultrasound we can evaluate the intestinal wall thickness and see whether it appears thickened.  If the intestine is thickened, we can determine which layer of the intestine is thick and then can make a list of diseases (inflammatory bowel disease, lymphoma, etc) that could be causing the problem.  We can also evaluate the pancreas to see whether any signs of pancreatitis are evident.

Another case that ultrasound may be helpful would be to evaluate elevations in a dogs liver values.  In older dogs elevations of liver values can be benign or could indicate the start of a more serious condition.  With ultrasound we can evaluate the structure of the liver and possibly get an aspirate or biopsy sample to evaluate for a more serious condition.

Ultrasound on a dog

The nice thing about ultrasound is it that it is a non-invasive procedure.  We only have to shave the underside of the belly (and possibly sedate your pet) to get good images and a possible diagnosis.  Like any test, it may not give us all the answers, but many times can give us a lot more information that can benefit your pet greatly.

Ultrasound image of a kidney

Please let me know if you have any questions.

Oh my gosh, is that a Tick?

Nothing creeps people out more than finding a tick on their pet (or themselves for that matter).  Because of pets hair it can be difficult to find ticks on your pets until they have been feeding for a few days and become engorged.  When this is the case we can get concerned because ticks do transmit several diseases that are transferred to animals after the tick feeds.  First, lets talk a little about the tick life cycle.  Ticks have 4 life stages: egg, larva, nymph, and adult.  Depending on the species this cycle can take a year to 2 years to complete.  The larva, nymph, and adults all can feed on mammals.

In Illinois there are numerous tick species, but the most common that may be encountered are the American dog tick, lone star tick, blacklegged (deer) tick, brown dog tick and winter tick.  Most species are active in the spring and early summer and then are more dormant throughout the rest of the year (however, ticks can be active any time of year when temperatures are above 45 degrees).  Ticks hang around on the tips of grasses and scrubs (not trees) and when the plant is brushed by a pet or person they crawl onto the host.  Using their mouth pieces they attach to the skin and feed on the blood of the host.  When they bite, ticks typically secrete saliva that has anesthetic properties, so the bite is not felt.  Ticks can feed for several days and become quite engorged prior to falling off.

Why is it important to try and prevent tick bites?  When ticks feed on blood, they can also transmit diseases to the host they are feeding on.  Common diseases that are passed include Rocky Mountain Spotted Fever, Lyme disease, Erlichia, Anaplasmosis, as well as other blood-borne pathogens.  Many of these organisms attack red blood cells, white blood cells, blood vessel lining cells and other cells in the body and can have serious, and possibly life threatening consequences.  So, it is much more advantageous to prevent attachment of ticks then to treat the diseases that may be passed along by a tick bite.  

How do you go about preventing tick exposure.  There are numerous products available that help repel ticks.  Many of the products are topical spot-on liquids that go on the back of the shoulder blades and last for around a month.  These products also typically protect against fleas.  Frontline and Advantix have been around for awhile and work fairly well.  Be cautious with using Advantix (dog only product) in a household with cats because it contains a permethrin which can cause problems (seizures, tremors) in cats.  Merial (the maker of Frontline) recently came out with another product called Certifect, which is the active ingredient in Frontline plus an added ingredient (amitraz) which helps repel ticks more strongly.  

There is also a very good product called Preventic, which is a collar containing amitraz that is put around the neck.  It starts working within 24 hours of application and lasts for 3 months.  This collar works very well and we don't see many side effects associated with it.  Occasionally, owners of pets with a Preventic collar may have a skin reaction when petting their animal.  Also, if ingested the collar can cause major issues, so if you have a pet who is good at getting collars off, this may not be the product for you.

What if you find a tick on your pet?  If the tick is not attached, simply remove the tick and dispose of it outside or in the garbage.  We will put them in alcohol to kill them prior to throwing them out.  If they are attached, then the tick should be removed.  Grasp the head of the tick as close to the skin as possible and pull straight out.  If you are not comfortable doing this, then contact your veterinarian and they can do it for you.  If the tick is engorged and you are in an area where ticks carry diseases (see above), then watch your pet closely for any signs of sickness (inappetence, lameness, lethargy).  Some veterinarians will start prophylactic antibiotics in this situation to treat tick-borne diseases.  Others may wait and suggest running tick-borne antibody titers in 8-12 weeks after exposure.

Ticks can cause huge problems, so it is best to prevent them in the first place.  Let me know if you have any questions.

So Many Choices...

With the start of Spring (and finally spring weather) it is always a good time to review heartworm and flea protection for your pet.

Heartworm disease is a parasitic infection that is passed by mosquiotoes when they feed on your pet.  Any pet is susceptable even if they don't spend a lot of time outdoors.  If you can imagine those warm summer nights sitting out on the porch (even if just for 5 minutes) and coming back in with what seems like hundreds of mosquito bites.  Well, those mosquitoes don't just feed on you and will look for any warm body to feed on; like your pet.  That being said, it is important that your pet (in particular dogs, but cats as well) be on a montly heartworm prevention.

Same goes for fleas.  You can see the previous post to get a more detailed discussion on fleas.  Basically, the moral of the flea story is it is much easier to prevent them than to treat your house after they have gotten out of control.  Fleas love to feed and love to multiply and if your pet is not protected they are a prime target for fleas.  Even if your pet only goes out for a short time (let's say to use the bathroom), that is long enough for a flea to hop on them and then come into the house and lay its eggs.  Because of this we recommend all pets be on a flea prevention.

Now that you know your pet should be on a heartworm and flea preventative, what preventative should you use?  Recently, it seems like there has been an explosion of different products available for prevention of heartworms and fleas.  Our clinic focuses on a couple of products that we believe work well. 

The first is a product called Trifexis.  The nice thing about this product is it prevents most of your major parasites all in one oral monthly tablet (Heartworms, Fleas, and Intestinal Parasites).  It is well handled by dogs with vomiting being the most common side effect.  We feel that it works very well for fleas; killing adult fleas in as quickly as 30 minutes.  The heartworm prevention in the medication is the same active ingredient as Interceptor, which has proven effective for a very long time.  The one downside with this medication is that it does not prevent against ticks; however, we have been adding in a Preventic collar in dogs at risk for tick exposure.

The other product or combination of products that we use is Heartgard and Frontline.  Heartgard prevents heartworm disease along with intestinal parasites.  It has been around for a long time and works very well.  It comes in a flavored tablet, so administration is easy.  Frontline is a topical flea and tick preventative (goes on the skin over the back).  It also has been around for a long time and works well, but you need to make sure that it is applied correctly.  It uses the natural oils of the skin to spread, so you have to make sure you do not bathe your pet or allow them to swim two days before or after application.  After that time it is water-resistant.  You also have to make sure that when applying the medication it get down to the skin and not just on the hair.  Both products are administered on a monthly basis.

There are numerous other products available, which likely are effective as well.  It is important that your pet be on one of these products as heartworms can be devastating to an animal and fleas not only are a nuisance, but can spread disease as well. 

Why a 1 year vaccine?

There are a few vaccines that we deem as "core" vaccines that are highly recommended in cats.  One in particular is a vaccine against the rabies virus.  Fortunately, in most area of the United States (Illinois included), rabies is not a huge problem and only few cases of rabid animals and very rare cases of human exposures are reported.  One of the main reasons for this is the implementation of rabies vaccines in our pet population, who can be carriers and propagators of the disease.  In areas were mandatory rabies vaccination of pets and wild dogs is not required (such as India) rabies is a huge problem with over 20,000 people killed each year.



You may say that my cat is indoor only, so I don't think they need to be vaccinated as they won't be exposed to any other potential carriers of the disease.  This may be true, but in our area the most common carrier of the virus are bats, which on occasion to get in the house and may cause exposure to your pet.  Because of this, the public health concern, and the fact that County laws requires it, we highly recommend that your cat be vaccinated against rabies.

Okay, now that we have decided that we should vaccinate your cat for rabies, what is the best vaccine to use?  There are a few vaccines available that are effective in protecting your cat from rabies.  The one that we recommend is the Merial PureVax vaccine.  This uses a recombinant canarypox-vectored vaccine technology.  Basically what that means is they take little snipets of the rabies virus' DNA and implant them into the DNA of a canarypox virus.  Once this is injected under the skin, your cat's body recognizes the canarypox virus as a foreign virus, so mounts an immune system response to fight off the virus.  In doing so, the body also mounts a response to the snipets of the rabies DNA, which gives your cat protection against rabies.  We rarely see side effects to the virus and are very happy with the results.  The one downside to this vaccine is that it is only labeled for protection for 1 year, so has to be boosted annually (as County laws are strict about following the labeled protection).



Why do we use the 1 year vaccine over available 3 year vaccines?  The main reason that we do this is safety.  In the late 90's and early 2000's, the veterinarian community noticed an uptick in aggressive skin tumors call fibrosarcomas.  When looking at cats with these tumors they noticed that many of them were occurring over the shoulder blades where most vaccines were previously given (lots of loose skin here that made for easy administration).  Pathologists looking at these tumors under the microscope also noticed that they saw some foreign material that could be associated with previous vaccines.  Many vaccines use a slightly different technology for vaccines where a portion of killed virus is added with an adjuvant and injected under the skin.  The adjuvant is a caustic substance (usually not disclosed by the vaccine maker) that is meant to stimulate the immune system to react and subsequently react to the killed virus (which is typically too weak to stimulate the immune system itself).  It was hypothesized that the adjuvant was doing such a good job that it caused chronic inflammation in these areas that eventually would end up transforming into cancerous cells.



Planning for removal of large tumor on the back.

 These tumors are very aggressive and tend to metastasize (spread to other organs like the lungs) readily and without extensive surgery (sometimes removing parts of the scapular bones or chest wall) tend to grow back quickly (as soon as 2-3 months).  Even with extensive surgery these tumors can recur or spread and many cats don't make it longer than 1.5-2 years after they are diagnosed.

A cat after removal of a vaccine associated fibrosarcoma

In response to these tumors, a company switched to the canarypox vaccines and we have seen a declined in these tumors.  Because of a problem with a control group during testing of the vaccine, the vaccine was unfortunately denied a 3 year label, so we are stuck with the 1 year vaccine for the time being.  However, the safety of the vaccine (in my opinion) outweighs the inconvenience that may come with a 1 year vaccine.

Please let me know if you have any questions.

Food Allergies

Now that we have discussed environmental allergies, we should discuss other possible causes of itchiness in pets, in particular food allergies.

Does my pet have a food allergy?

Diagnosing a food allergy can be difficult with pets.  The only reliable way to judge whether a pet is having a reaction to food is performing a food elimination trial which can be cumbersome and lengthy, but if an owner is committed can be very rewarding.  If your pet has itchiness throughout the year and it tends to be around the feet and ears, then a food allergy should be strongly considered.  The allergies tend to start prior to a year of age, but can start anytime throughout a pets life (even if they have been on the same diet for a long time). 

Well, does my pet have a food allergy?

If you think your pet is allergic because they are itching a lot and go to the veterinarian’s office, they will likely ask you a series of questions to get a handle of what is going on.  There are some common criteria that food allergies fit into:

1.      Young age of onset: Most pets with food allergies start showing symptoms prior to one year of age.  In a dog who develops itchiness after 6 years of age with no history of previous problems, a food allergy should also be suspected.

2.      Time of year: A food allergic pet should be itchy during all times of year, since they are being constantly exposed to the allergen.  Some pets may show worsening symptoms during certain times of year because they have a concurrent airborne allergy.

3.      Response to steroids: Food allergies typically do not respond well to steroids.  In early stages of food allergies, the itchiness may improve.  If your pet once responded well to steroids and now doesn’t, then a food allergy should be suspected.

4.      Areas of itchiness: The typical adage for food allergies is, “ears and rears.”  That being said the distribution can be elsewhere including

5.      Concurrent gastrointestinal signs: Around 20% of food allergic dogs will also have consistent or intermittent gastrointestinal signs (vomiting or diarrhea).

We suspect my pet might have a food allergy, now what?

The “gold standard” for diagnosing a food allergy is an 8-12 week food elimination trial followed by rechallenging your pet with their previous food.  If your pet improves on the food trial and then symptoms reoccur after reintroducing their previous food, then a food hypersensitivity is diagnosed.  The offending agents in the food that cause problems are the proteins.  Common proteins that cause problems include beef, milk, lamb, wheat, corn, chicken egg, soy, chicken in dogs, and adding tuna and salmon to the list in cats. 

Prior to starting a food trial it is a smart idea to compile a list of foods that your pet has been exposed to in the past.  This includes any commercial dog diets, table scraps, treats, supplements, and drugs (particularly heartworm prevention).  We do not want to use a diet that has a protein source that your pet has already been exposed.  We also want to know whether your pet has unsupervised access outside as some pets forage outside and may be exposed to things that you may not know about.  Once we have a good idea about previous exposures we can make suggestions on foods for a food elimination trial.

What is a food elimination trial?

An elimination trial is a period of 8-12 weeks where a “hypoallergenic” diet is fed exclusively to your pet and their itchiness and skin issues are monitored and graded for improvement.  It is important that during this trial ONLY the chosen diet is being fed.  Your pet should not have any treats (table scraps, biscuits, popcorn, etc) during this time and any flavored medications (in particular heartworm preventatives) should be stopped (if during the summer a topical or unflavored heartworm prevention should be used).  

ONLY the “hypoallergenic” diet should be fed during this time.  If your pet has a food allergy and the diet chosen is the proper one for him/her, then you should only see improvement on the diet trial.  If your pet ever gets worse symptoms (AND you are sure that they did not receive any outside food source), then the food trial should be stopped and a different diet should be chosen.  Improvement are not always immediate, so we suggest giving a minimum of 8 weeks to see whether any improvement is noticed.

If your pet improves on the food and is doing significantly better, then we suggest following up with a “challenge” of their previous food.  Prior to starting the new diet, save some of their old food and freeze it for the challenge.  The “challenge” involves reintroducing the old diet.  If your pet has recurrence of the itchiness and skin issues (usually show up between 15 minutes after eating, but some can take as long as 2 weeks), then the food allergy is diagnosed and one of the protein sources from the old diet is the offending allergen.

What food should I use for the elimination trial?

There are a few routes that can be taken for the type of food used during the trial:

1.      Homemade diet: The home cooked diet is a simplified diet of one protein source (1 part) and one carbohydrate source (2 parts).  Although this is not balanced (minerals and vitamins), it is not meant to be fed long term and will not cause major problems if fed for the 8-12 weeks.  Protein sources currently available for home-cooking include kangaroo, camel, ostrich, emu, bison, elk, venison, rabbit, duck, fish, and whole chicken egg.  Carbohydrate sources can include oatmeal, quinoa, rutabaga, sweet potato, and white potatoes.  Ideally, a protein and carbohydrate that your pet has not been exposed to should be used.  This simplified diet eliminates any other food source and is very effective.  Once we have identified that your pet is food allergic (improvement on this diet), then we can seek out a commercial dog diet with similar ingredients that can be used or consult with a veterinary nutritionist to help balance the homemade diet so your pet will not be vitamin or mineral deficient.

2.      Prescription novel protein diet: These diets use a similar idea as the homemade diet as they use protein and carbohydrate sources that are novel.  Common ingredients include duck, kangaroo, venison, potato, green pea, or rice.  Companies offering these diet include Royal Canin, Science Diet, and Purina and these diets have to be obtained through a veterinarian.  The companies are very throughout about preventing cross contamination of foods during production and guarantee that the proteins listed are the only ones in the diet.  The advantages of these diets are the convenience of not having prepare the diet and knowing that there is no cross contamination.  The disadvantage is the price which typically run $33 for an 8# bag, $64 for an 18# bag, and $84 for a 28# bag. 

3.      Prescription hydrolysed diet: These diets are a little different in that instead of using novel proteins they process the proteins so they are very small and should not cause an allergic reaction.  They have similar advantages and disadvantages as the prescription novel protein diets.  Some pets do also have some gastrointestinal issues (mostly diarrhea) with these diets.

4.      Over-the-counter limited ingredient diets: These diets are similar to the prescription novel protein diets in that they use protein and carbohydrate sources not typically seen in commercial diets.  The disadvantage is that there may be some cross contamination during the production process that can leave small amounts of other common proteins (beef, chicken, etc) in the foods.  These proteins can be at high enough levels to continue to cause adverse skin problems.  The advantage is that they are typically cheaper than the prescription brand foods: $15 for 5# bag, $40 for #15 bag, and $58 for a 28# bag.  If choosing this option, I do like the Natural Balance Limited ingredient line.

Just because you start on one diet it doesn't mean that you have to continue on this diet forever.  You can use a prescription novel protein diet or homemade diet for the diet trial and if you see improvement, we can try to find an over-the-counter alternative that may do a similarly good job.  Using the prescription diet or homemade diet first at least makes cross-contamination from other proteins less likely and we can rule out a food allergy much easier.

I am not seeing improvement on the food trial, now what?

Please be patient with the food trial.  It can sometimes take 12 weeks to see a major improvement in skin issues with dogs on a new diet.  Try to make a conscience effort to grade your pets skin issues every 2 weeks.  You should see gradual improvement in itchiness over time if the food trial is working.  If there is ever a worsening of signs (AND you are certain your pet didn't get any other food and it is not the time of year for seasonal airborne allergies) then your pet may not have a food allergy or the diet being used is not appropriate.  Please contact your veterinarian to discuss things further.

Here is a website that discusses common pitfalls of food trials.  

More Allergies

How can we test my pet for what they are allergic to?

The first point to be made about allergy testing is that testing should only take place after a diagnosis of an airborne allergy is made.  A diagnosis is made by clinical signs and your pet fitting many of the criteria that have previously been discussed.  The reason that a diagnosis should be made first is testing is not 100% accurate and there is the possibility of false positives.  This means that pets without allergies can have positive responses to allergy testing.  The second point to discuss before testing is why we are testing.  The reason we are performing “allergy testing” is to identify what allergens are causing a problem, so we can make a solution with these allergens to perform immunotherapy.   We will talk about immunotherapy shortly.

There are two ways to test for what your pet is allergic to:

      Intradermal skin testing (IDST): For this procedure your pet is sedated and a patch of hair is shaved on his/her side.  Small amounts of concentrated allergen (pollens, molds, grasses, weeds) extract are then injected under the skin and the reaction to the allergies are measured.  Allergens that your pet is allergic to should puff up and become red.  In order to get accurate results on these tests your pet will need to be off of antihistamines for a minimum of 2-4 weeks and off steroids for at least 4-6 weeks.  This testing does typically require referral to a veterinary dermatologist and the usual cost is ~$380.  This is considered the “gold standard” for allergy testing.  The best time of year to test is usually in the early fall (Sept/Oct).

      Serum antibody testing: This is a different way of testing for allergies in pets.  The pros of this test is that it does not require referral, only requires a blood draw, and typically your pet does not need to be off of steroids or antihistamines for testing.  The drawback is that you can have some false negative or positive results (this is true for any testing).  For this test the amount of antibodies (specifically IgE which is associated with allergies) to specific allergens are quantified.  Those allergens with higher antibody levels are deemed the problem allergens.  The cost for testing is ~$200.

It is possible with both tests to get negative results (no reaction to allergens).  For dogs that obviously have an allergy problem there can be a few reasons for negative tests including:

1. Improper withdrawal of steroids/antihistamines

2. Wrong time of year for testing

3. Improper choice of allergens being testing

If your pet has a negative allergy test, then it may be suggested to try the other type of testing (IDST versus serum testing or vice versa).

My pet had allergy testing performed, now what?

Once your pet has been allergy tested and the offending allergens are identified, then we can proceed to immunotherapy.  Immunotherapy involves making a solution that contains small amounts of the different allergens that your pet is allergic to.  This solution is then injected under the skin (or more recently placed under the tongue) every few days.  There is an initial induction phase (6-10 weeks) where the solution is dilute and then over the next few weeks the amount given and the concentration of the solution are increased.  Once we have reached the maintenance phase, your pet will be getting injections every 1-2 weeks.    Many dogs (60-70%) show improvement with immunotherapy.   This does not necessary mean that the itching symptoms will go away completely.  In many cases, pets may need additional therapy (anti-histamines or steroids) during certain times of year, but hopefully the dosage, frequency and length that these medications are needed will be reduced.   The improvement are not immediate either.  Pets typically take 3-5 months to show improvement and in some cases can take upwards of a year.  The cost per year for a typical dog on immunotherapy is ~$620.  This therapy is typically continued life long, but in some instances can be stopped after a few years of therapy.

Allergies

Although it is not the time of year for allergies to hit, it is always a conversation I have with owners (whether it be at work or when I mention I am a veterinarian to something).  I figured it would be a good topic to hit on.

Is my pet allergic?

Most people are familiar with allergies in people and may even have allergies themselves.  They avoid going outside in the spring when the trees are pollinating or don’t go over to a friend’s house because of a pet.  Who wants a runny nose anyway?  Well, dogs and cats can also have allergies, but instead of runny noses or sneezing they tend to get problems with their skin, specifically itchiness.  It can make pets miserable at times, but fortunately we have ways to help relieve some of the symptoms and in some instances can almost cure the condition.

Well, is my pet allergic?

If you think your pet is allergic because they are itching a lot and go to the veterinarian’s office, they will likely ask you a series of questions to get a handle of what is going on.  There are some common criteria that environmental allergies fit into:

Young age of onset: Most pets with airborne allergies start showing symptoms between 6 months and 3 years.  It is typically after the second exposure that symptoms develop.

2.      Seasonality: Airborne allergies typically show up during certain times of year.  Spring is bad for tree pollens, summer for grass, and fall for weeds.  However, if your pet is allergic to dust, dust mites, food mites, or molds, then they may have year round problems.

3.      Response to steroids: Itchiness should respond very well to steroids in allergic pets.

4.      Areas of itchiness: Pets who have localized itchiness in their feet (imagine white dogs with brown feet from saliva staining) typically have an allergy.  Other common areas are the arm pits, feet, around the muzzle and eyes, ears, and butt area.

What are some other possibilities for my pet’s itchiness?

Airborne allergies are not the only cause for itchiness in pets.  There are other things that can cause itchiness as well and should be considered or ruled out before treating your pet.  This may require a few simple tests including cytology of the skin and a skin scraping (both look at material on the skin under the microscope).  Here are a few things that we try to rule out:

1.      

      Other allergy: Pets can have allergies to other things.  The other more common allergies include flea allergies and food allergies.  There are a number of good flea preventatives that can be used along with treating the local environment that can help rule this out.  A “hypoallergenic” diet for 8-10 weeks without any other food sources can rule out a food allergy.  Of course it is not that simple as pets can have multiple allergies as well.

2.      Simple infection: Pets can get infections with yeast or bacteria that can mimic allergic symptoms.  Treating for the infection with resolution of the itchiness and no recurrence is a good indication that the problem was an infection.

3.      Scabies: These are mites that live in the outer layer of the skin.  If these are causing a problem, then all pets in the house are typically itchy, you may be itchy, and typically the ears and elbows are more affected.  Treating with a trial of Revolution (topical spot-on product) for three times two weeks apart can rule this out as skin scrapings don’t always uncover these mites

OK, we are pretty sure my pet is allergic to something in the air, now what?

Once we have come to the diagnosis of an airborne allergy there are a few ways of tackling the problem.  The main ways of helping your pets are 1.) Symptomatic therapies 2.) Avoiding the offending allergen 3.) Allergy testing with immunotherapy injections.

What are the options for symptomatic therapies?

There are a number of drugs available that can help with your pet’s itchiness.  The first thing that we would want to do is treat any concurrent infection.  This is typically done with a combination of oral medications (antibiotic or anti-yeast depending on the problem) and shampoos.  Once we know any infections are under control, then we can try and control the itchiness.

  

      Antihistamines: Although these are not the strongest against fighting the itch, some pets (~15%) respond very well to antihistamines.  I typically recommend trying the medication for 7 days to judge whether there is a response.  Some pets respond better to one antihistamine over another, so you may want to try a few before judging whether or not they help.

a.      Loratidine (Claritin): 0.25 mg/lb once daily, available 10 mg tablet

b.      Cetirizine (Zrytec): 0.25 mg/lb once daily, available 10 mg tablet

c.      Diphenhydramine (Benadryl): 1-2 mg/lb 2-3 times daily, available 25 mg tablet

d.      Chlorpheniramine: 2-12 mg total dose 2-3 times daily, available in 4 mg tablet

e.      Fexafenadine (Allerga): 0.5-1 mg/lb once daily, available in 30 mg (children’s strength)

2.      Steroids: The typical one used is prednisone.  These typically work better than antihistamines to help relieve the itch; however, they do tend do have more side effects.  Minor side effects can include drinking and urinating more, eating more, and occasionally a personality change.  More serious side effects (typically happen when on chronic steroids) are immunosuppression, muscle loss, and making prone to diabetes.

3.      Omega fatty acids: These are typically given in the form of fish oil.  They interfere with the inflammation of the skin that is causing the itchiness.  The usual dose is around 500 mg per 20 lbs, but it is hard to overdose with this medication.  The 500 mg is the active ingredient (DHA + EPA), so make sure you look at the label on the back as it can differ from total mg label on the front.  Usually a double strength product is best.  These can be given whole or broken over the food.  There are also specially formulated foods that have higher doses of omega fatty acids that can be tried (i.e. Hill’s J/D).

4.      Cyclosporin: This medication works very similar to prednisone by suppressing the inflammation in the skin causing the itchiness.  The advantage over steroids is a reduced amount of side effects, particularly the drinking and urinating.  The major downside is cost.  At full strength for a typical 20 lb dog the cost per month is ~$115.  This is typically the starting dose and many times can be reduced after a month or two, but you are still looking at a minimum of ~$65-70 monthly.

5.      Topical therapy: There are many products that can be used topically that help with allergies (shampoos, conditioners, etc).  Recently, a new theory that allergic pets are deficit in certain proteins in the skin has emerged and in response companies have made topical spot-on products to help supplement these deficiencies.

I will talk a little more about allergy testing and immunotherapy in an upcoming post.  I thought this was enough to talk about for now.