Category Archives: Allergy




Immune modulator


By Dr. Karen Burgess


Brand name and formulations



What is Apoquel used for?

Apoquel is labeled for the treatment of itch associated with allergies.  It is in general a very effective tool in the management of allergies for pets.  There are many other immune modulatory uses for Apoquel that are being discovered daily.  Apoquel begins controlling itch within four hours of administration and can be used short or long term safely.

What is Apoquel?

Apoquel is an inhibitor of a specific mediators of inflammation, JAK1 and JAK3(Janus Kinase).  JAK1 is one necessary component in the cascade of events that lead to an allergic response, typically “itchiness” and inflammation in dogs.  By using Apoquel this process can be safely interrupted.

How is Apoquel given and what if a dose is missed?

Apoquel is typically prescribed for once daily dosing after an initial two week course of twice daily administration.  If a dose is missed and it is less than 12 hours late, go ahead and give the missed dose.  If it is within 12 hours of the next dose, skip a dose and resume regular schedule with the next dose.

Are there any side effects associated with Apoquel use?

In rare instances pets may experience vomiting, diarrhea, loss of appetite, or lethargy.

Who should not take Apoquel?

Apoquel should not be taken by pets being given immunosuppressive or immunomodulatory drugs.  Examples of this include prednisone and cyclosporine.  Apoquel is not approved for animals less than one year of age, pets with cancer, or generalized demodex infections.

What follow up is necessary with Apoquel use?

Laboratory work should ideally be done prior to use and then annually thereafter.



By Dr. Karen Burgess

What is conjunctival tissue?
The conjunctiva is the pink fleshy tissue that covers the eye and tissue surrounding it.  In a cat or dog with healthy eyes this conjunctiva should not be easily seen.  In cases of conjunctivitis where the conjunctiva is inflamed owners will often notice angry red tissue near the eyelid.  The conjunctiva is made up of mucous secreting cells similar to that found in the mouth and nose and serves to help protect and lubricate the eye.

What are symptoms of conjunctivitis?
Mild cases of conjunctivitis may appear as increased tearing that is clear or colored in nature.  More severe cases can develop swollen pink or red bulging tissue that appears to almost cover the eyeball.  The eye may become increasingly painful causing a pet to hold it shut or paw/rub at eye.  In severe cases it may be difficult to see any part of the normal eye.

Why do cats and dogs develop conjunctivitis?
There are numerous reasons for the conjunctiva to become inflamed.  Infectious causes include viruses and/or bacteria.  In some cases infections will develop secondary to some other underlying cause of conjunctival inflammation.  For cats viral conjunctivitis is extremely common and closely related to upper respiratory viral infections they are exposed to at a very young age.  In several of these situations the cat may recover from the initial infection but the virus remains dormant in their body reappearing later in life at times of stress or illness.  Non-infectious causes of conjunctivitis are typically related to the anatomy (size, shape, and location) of the eyeball itself.  Dogs often develop a condition where they stop producing tears which then leads to a “dry eye” and secondary conjunctivitis.  Some breeds of cats and dogs are more prone to having flat faces or bulging eyes which can change how the eyelid sits against the eye.  In these cases eyelashes or facial fur may rub against the eye and conjunctiva causing inflammation.  Allergic disease, foreign material caught in the eye, tumors, and immune disease are all additional causes of conjunctivitis.

How is conjunctivitis diagnosed?
A veterinary examination will typically reveal the presence of conjunctivitis.  Additional testing of the cornea and tear production may also be necessary.  If systemic disease is suspected bloodwork may be recommended.  In complicated cases referral to an ophthalmologist may be recommended.

What are treatment options for conjunctivitis?
Definitive treatment of conjunctivitis involves diagnosing the underlying cause for treatment and controlling secondary bacterial infections.  This may involve topical drops or ointment, oral medications, eye lubricants, or surgery.  It is important to protect the eye from self-trauma by using a protective collar or Elizabethean collar.  Pain medication may also be prescribed to help with associated discomfort.

What is the prognosis with conjunctivitis?
Prognosis is directly related to the ability to treat the underlying condition causing the inflammation.

Food Trial, Canine

Food Trial Procedure
By Dr. Karen Burgess

A food trial involves feeding a novel protein and carbohydrate source diet to a pet for six to twelve weeks.  During this time clinical signs are monitored for improvement.  Eighty percent of animals will have responded by six weeks but the remainder can take up to twelve weeks.  Committing to a food trial needs to involve all family and friends that come in contact with the pet.  It is imperative that no other food, treats, or potentially contaminated toys be offered for the duration of the trial.  Specific hypoallergenic treats may be recommended or kibble used as treats.  While prescription diets may seem more expensive, if they solve a pet’s problem they typically prevent discomfort and save money in the long run.  Additionally, all prescription diets come with a 100% guarantee even if opened.

There are two specific categories of hypoallergenic diets available.  The first contains a “novel” or new protein and carbohydrate source.  Since many dogs and cats have now been exposed to lamb, fish, and even venison, common proteins in these diets include duck, rabbit, and kangaroo.  Clients often wonder why an over the counter limited ingredient diet is not a viable option.  In a recent study three out of four commercial venison diets claiming to contain no soy, poultry, or beef tested positive for at least one of these antigens/proteins.  Prescription novel protein diets are manufactured and tested rigorously to ensure no cross contamination.

The second form of hypoallergenic food is made with hydrolyzed protein which is a conventional protein (such as chicken or soy) that has been reduced to a moleculer size that the immune system cannot recognize and thus react to.

Some owners are interested in home cooked hypoallergenic diets.  While a viable option, these diets tend to be more labor intensive and end up being more expensive than prescription diets.  If using a homemade diet long-term it should be formulated specifically for your pet by a veterinary nutritionist.

Regardless of type of diet used, please consult with your veterinarian regarding appropriate feeding amounts.

 Treat suggestions during a food trial:

  •       Blenderize food trial kibble with water and a little honey into a doughy consistency, ball          up to treat size and store on wax paper in a refrigerated plastic container
  •       Canned version of food trial diet if available
  •       If using oat based diet, thick cooked Quik oatmeal with a little honey, store as above
  •       Kongs with food trial kibble or above dough on the inside
  •       If potato based diet, baked frozen French fries


By Dr. Karen Burgess

What is pyoderma?
Pyoderma is another way of saying bacterial skin infection.  Skin has bacteria present naturally, but when allowed to overgrow skin infection develops.

What causes pyoderma?
Pyoderma is an overgrowth or invasion of the hair follicle with bacteria.  Typically pyoderma is secondary to some other cause.  Examples include allergic skin disease (atopy), food allergy, matted hair, self-trauma, and underlying metabolic disease (hypothyroidism, Cushing’s).

What are the signs of pyoderma?
Superficial pyoderma affecting only the outer skin layers often appears as red bumpy areas that have crusts present.  Hair loss or rough hair in the area may also be present.  Deeper pyoderma can cause significant hairloss and open wound like lesions.  In either case pets are often itchy and may paw or lick excessively at effected areas.

How is pyoderma diagnosed?
Visualization of lesions, history, and cytology of affected sites looking for bacteria are all involved in the diagnosis of pyoderma.  In severe or chronic cases additional testing to rule out underlying medical conditions may be indicated.

How is pyoderma treated?
Mild localized cases of pyoderma can often be treated with medicated sprays or shampoos.  More severe instances often require oral antibiotics until well beyond resolution of lesions.  An Elizabethean collar is often essential in treatment to prevent pets from further self mutilation while medications are taking effect.  Treatment of underlying medical conditions (ex. allergies, parasites) that predispose to pyoderma is also necessary.


By Dr. Karen Burgess

What is atopy?
Atopy is another way of saying airborne allergies or environmental allergies.  In people atopy would be known as asthma or “hay fever”.   Allergens are found in the environment and may be inhaled or come in direct contact with the skin.

What are signs of atopy in pets?
The most typical presentation is itchy skin, secondary skin infections, and ear infections or inflammation.  Symptoms may be seasonal in nature or year round depending on the underlying allergen.  All areas of the body can be affected, but in dogs the face, armpits, abdomen, feet, and legs are often predominant.  Dome pets may have a red color to their fur from licking (saliva contains a pigment that thus stains the fur).  Cats can have lesions anywhere on their body.  Ears are a continuation of the skin inside so infections are common secondary to atopic inflammation of the ears.  Respiratory signs can occur in pets but are much less common.  Symptoms often start between 1 and 3 years of age and will usually get worse over time not better thus making treatment essential.

What causes atopy?
Just like in humans, allergies are an inappropriate and excessive response of the immune system.  Essentially instead of ignoring an allergen such as dust or mold, the immune system becomes overly excited at any exposure leading to inflammation of the skin for pets.  Genetics also play a part with certain breeds having a higher incidence of atopy.

How is atopy diagnosed?
Clinical signs and history are very helpful in identifying atopy as a cause of chronic itching or skin disease.  The first step is ruling out other causes of itchy skin, in particular parasites (mites, fleas, lice), secondary bacterial or yeast infections, and systemic diseases (hormonal diseases, cancer).  The next step is determining whether food allergies may be a factor.  Pets can experience both food allergies and atopy and symptoms for both overlap, but their treatment is very different.  Once all other possible causes of chronic itching/skin disease have been ruled out then atopy is the most likely diagnosis and definitive testing can be performed.  Skin (intradermal) testing has for years been considered the gold standard.  Similar to in humans, an area of skin (typically on the side of the body that has been shaved) is pricked with a variety of potential allergens and the subsequent response is measured.  This information is then used to create injections that are used for treatment.  Prior to testing steroid and antihistamine therapy must be discontinued for a period of time.  Sedation is necessary for skin testing.  Blood allergy testing has become more reliable; this method measures the pet’s antibody levels toward a particular allergen.

How is atopy treated?
There are many ways to manage or treat atopy.  A few are listed here.

  1.  Minimize exposure– Avoidance or removal of specific allergens (washing feet after going outside, frequent baths)
  2. Hyposensitization (“allergy shots”)- Information obtained from allergy testing can be used to design specific immunotherapy.  By giving small doses of allergens at a regular interval, the pet hopefully develops tolerance to them and thus reacts less when encountered in the environment.  Unlike in humans, pets do not outgrow allergies like some humans.  These injections are typically given by owners at home and are found to be effective in 75% of treated dogs.
  3. Immune modulators– Atopica (cyclosporine) is a non-steroidal medication that alters how the immune system responds to an allergen.  While safe and effective, this product can be expensive particularly for larger dogs.  Corticosteroids (such as pred) act as an anti-inflammatory and immunosuppressive agent.  While very effective at controlling symptoms and inexpensive, steroids have a myriad of negative side effect and are not a safe chronic long-term solution.
  4. Antibacterial/antifungals– It is common for pets with allergies to develop secondary bacterial or fungal injections.  In essence pets with allergies have “sick skin”.  While bacteria and yeast are found naturally on the skin, it is easy for their numbers to get out of control for pets with allergies.  For severe infections or overgrowth, oral antibiotics or antifungals may be necessary.  In milder cases topical products may be sufficient.
  5. Antihistamines– Commonly used to control allergy symptoms in humans, antihistamines such as Benadryl are far less effective in dogs and cats.  The mechanism of action is to block the chemicals causing the itch (typically histamine).  Any particular antihistamine may help only 10-15% of pets.  Trial and error is necessary to determine which if any might be beneficial for an individual pet.  Overall antihistamines offer a safe and inexpensive adjunct to atopy treatment.
  6. Omega 3 supplementation– Often referred to as fatty acid or fish oil supplements, Omega 3s overtime can decrease the inflammation associated with atop.  DHA and EPA are the common fish origin omega 3 fatty acids.  When determining a dose the sum total of DHA and EPA is used with a target of 70 mg/kg/day (range 50-100 mg/kg/day).  Fish oil supplements are a supplement and thus not well regulated.  Reliable brands include Nordic Naturals (online human product) and Welactin (veterinary product).
  7. Topical treatments– Shampoos, conditioners/lotions, and sprays can all be very useful in controlling allergic skin disease.  Medicated shampoos need to be used frequently (two to three times weekly) and allowed to stay in contact with the skin for 10-15 minutes before rinsing.  While for some clients this is not the most convenient therapy, it allows a relatively inexpensive at home treatment option that is safe and does not involve systemic (oral) medication.  Sprays and lotions are used for specific or isolated areas.  Steroid sprays allow the potent anti-itch effect without the same negative side effects of oral steroids.
  8. Flea and tick preventative– Year round prevention of parasites is recommended to avoid this complication for the already itchy atopic pet.

Acne, Feline

Feline Chin Acne
By Dr. Karen Burgess

What is feline chin acne?
Feline chin acne is a condition affecting the hair follicles on the chin of cats which often resembles a dirty chin.  When this “dirt” is removed and on closer inspection, small raw or bloody bumps are often discovered.  Technically chin acne is a follicular disease where too much keratin (protective protein made by skin) is produced, trapped in the hair follicles thus leading to what are commonly referred to as blackheads.  These plugged follicles can then become infected forming pustules (otherwise known as pimples).

Why do cats get chin acne?
There is no one cause for chin acne. Contributing factors may include poor grooming habits of the cat, genetic tendency to produce too much sebum (a naturally produced oil produced by the skin glands), improper shedding of the hair thus leading to clogged follicles, or abnormal keratin production.

How do I tell if my cat has chin acne?
When looking at your cat’s chin it should be smooth and clean in appearance under the fur. If bumps, scabs, or a dirt-like substance are noticed then your cat may have chin acne. The chin may be painful and in severe cases fairly swollen. Chin acne may also affect the upper lip.

How does my veterinarian diagnose chin acne?
Often the clinical appearance is enough to diagnose chin acne. Additional testing of the skin for specific bacteria, parasites, or cancer may also be necessary.

How is chin acne commonly treated?
Better hygiene is typically the basis of treatment. Cleaning the debris off the chin allows for better penetration of medication which is often benzoyl peroxide based. In some cases clipping of the fur is also necessary. Medicated shampoos, pledgets, or ointments are often prescribed for use at home.  It often helps to first hold a warm moistened wash cloth against the area for a couple minutes to help open affected pores. In severe cases oral medications may also be necessary.  Removal of any plastic bowls is also recommended as there is some association between plastic exposure and chin acne. Prognosis for control or recover is good overall.

Anal Sac Disease, Canine

Anal Sac Disease
By Dr. Karen Burgess

What are the anal sacs?
Anal sacs, or anal glands, are two sacs found under the skin near a dog or cat’s rectum.  Located at approximately four and eight o’clock when looking at the anus, these sacs normally contain an often putrid dark colored fluid-like material that exits into the anus via small ducts.  Often considered to be “scent glands”, anal sac fluid is naturally released during defecation or at times of excitement or stress (similar to a skunk).  In the wild, dogs will mark their territory with anal sac material, rubbing their back ends against vertical surfaces to promote expression.

Why do pets develop anal sac disease?
It is unknown why our domesticated pets have anal sac issues.  It may be related to breed, weight, or underlying skin disease (the anal sacs are lined with cells similar to the skin).  Diarrhea or low fiber diets may also contribute to disease.

What are symptoms of anal sac disease?
Pets with anal sac disease often will scoot their bottoms or lick excessively at their anus.  In some pets the material in the anal sacs will become impacted or “plugged”.  The fluid in these cases is often thicker than usual contributing to swelling, blockage, and eventual infection.  With complete blockage, the anal sac can rupture through the skin near the anus leaving a large open wound or matted fur near the anus.  Pets with severe infection may show signs of general illness including lethargy, painful defecation, and anorexia.  If you suspect your pet has an anal sac abscess do not attempt to handle their back end as they may unintentionally bite due to pain.

How is anal sac disease treated?
An isolated episode may only require manual expression of the fluid in the anal sac.  This can be done externally but is more effectively accomplished by a trained professional rectally.  In cases of impaction or abscess, wound care (cleaning, flushing) with sedation is often necessary along with oral antibiotics, anti-inflammatories, and pain medication.  An Elizabethean collar will also be necessary to prevent further self-trauma.  Reevaluation by rectal palpation after infection resolution is necessary to ensure no residual disease or masses are present.

How is anal sac disease prevented?
There is no definitive way to prevent anal sac disease.  Some pets have their anal sacs expressed on a regular basis to prevent issues, but this may also contribute to their inflammation.  Weight control and exercise along with increased fiber intake (idea being that a bulkier stool increases stimulation and thus expression of anal sac material) may help prevent episodes.  In cases of recurrent anal sac disease, diagnostics for food or inhalational allergies (atopy) is recommended.  Surgical removal is an option, but should be avoided at all costs due to likelihood of complications.

Food Allergy, Canine

Food Allergy
By Dr. Karen Burgess

 What causes a food allergy?
Food allergy is responsible for 10% of allergic skin disease in dogs and cats.  It occurs when a pet’s body identifies a component of their diet as foreign or “bad” causing the immune system to respond.  Antibodies to the offending nutrient are produced which leads to inflammation in particular with the re-exposure that occurs with every meal.  The most common food allergens in dogs are beef, dairy, wheat, egg, and chicken.   In cats beef, dairy and fish are most problematic.  50% of food allergic cats and dogs are allergic to multiple components in the food.  Owners often think that a recent switch in food “caused” a food allergy when in actuality it takes time for these allergies to develop.

What is the difference between food allergy and food sensitivity?
Some pets have food sensitivity instead of a true food allergy.  This is a situation where pets do not tolerate a particular food component but are not having a systemic allergic response.  An example of a food sensitivity would be eating spoiled food or someone that was lactose intolerant.

What are common signs of food allergy?
The most common symptom associated with dog and cat food allergy is a non-seasonal itchiness that is not due to another cause such as parasites (i.e. fleas, mange).  Typically these signs develop prior to one year of age and are non-responsive to steroid therapy.  Common signs include recurrent ear infections, facial itching, and peri-anal itching.  Repeated skin infections and hair loss may also be noted.  Some pets will display gastrointestinal signs (vomiting, diarrhea, weight loss, flatulence) in addition to or instead of skin signs with food allergy.

How is food allergy tested for?
Clinical signs and history (in particular symptoms prior to a year of age) may be highly suggestive of a food allergy.  The only true way to diagnose a food allergy is to perform an eight to twelve week food trial using a veterinary approved prescription hypoallergenic diet (see additional information below on Food Trials).  If symptoms resolve this is a strong indicator that the pet is allergic to some component in their previous diet.  After completion of the food trial, pets are challenged with individual proteins or carbohydrates to see when they again become symptomatic (typically within two weeks of re-exposure).  The goal is to determine whether there is an over-the-counter diet that may be acceptable for long-term use.  Owners may continue the hypoallergenic diet indefinitely as it can often be difficult to transition successfully to a commercial product.  Some companies do offer blood testing for food allergies.  These tests are notoriously unreliable with numerous studies showing both false negative and false positive results.  An appropriately performed food trial is the only valid way of testing for a food allergy.