Doc, My Dog Has a Rash

itchy dog

Last month, Nationwide Pet Insurance announced the top pet insurance claims for the 650,000 pets they insure. The top four are skin issues. Number one and four are both skin diseases. Allergic dermatitis and pyoderma (skin infection) result in a skin rash which is the topic of this blog post.

Atopic or Allergic Dermatitis
Allergies are common in dogs and can be seasonal or non-seasonal. About this time of year, dogs with seasonal allergies start scratching and itching because pollen, mold or some beautiful spring plant is the source of their allergies. If your dog scratches year round, then the allergen might be dust, wool, feathers, or even the family cat! The itch-scratch cycle makes the skin red and inflamed. The itch-scratch cycle also sets off a cascade of events that can lead to infections in the hair follicle. Hot spots are a localized inflammation of the skin stemming from allergies. A severe hot spot can become infected with bacteria or yeast.

Bacterial Infection
A bacterial infection in the hair follicles is called pyoderma and was the number four most common insurance claim paid by Nationwide in 2017. If your dog has pyoderma, you will see a red, bumpy rash Pyoderma occurs most commonly as a result of allergies. Puppy pyoderma can be found on the tummy of puppies, likely because their immune system is not quite grown up yet. Flea bites, mange, clipper burn, and hair mats can also incite a skin infection. Licking and scratching a skin infection can make it much worse and is why veterinarians often recommend the dreaded cone in patients with skin infections.

Yeast Infection
Fungal or yeast skin infections are another allergy-induced skin problem. Certain breeds, like the West Highland white terrier, are predisposed to yeast skin infections, but any dog can get one. Face folds or skin folds in general hold moisture promoting the overgrowth of yeast which can be very itchy.

Ears Are Really Just Skin
The ear flaps are actually skin folded over on itself. Number two on the list of insurance claims is ear infections. Like skin infections, ear infections are tied to allergies. Follow your veterinarian’s instructions on managing the allergies and the ear infections will abate. Occasionally we see ear mites causing infections in dogs, but bacteria and yeast are much more common organisms causing an infection.

While clearly allergies are the most common cause of skin rashes, keep in mind systemic diseases such as Cushing’s disease and hypothyroidism may trigger a rash.

Seasonal Allergies and Your Pet

pet allergies

What do I need to know about allergies in my pet?

  • Some pets are more likely to get allergies due to their genetics
  • Certain breeds are more affected than others
  • Symptoms can start at any age, but most commonly start between 6 months and 3 years

What are the most common causes of allergies in pets?

  • Pollens (trees, weeds, grasses)
  • Molds
  • Dust
  • Wool
  • Animal dander
  • Feathers

What are the most common allergy symptoms?

  • Scratching, chewing and licking: most often under the arms, face, feet or stomach
  • Hair loss, salivary staining (brown stains around mouth or feet), redness
  • Bad-smelling thickly-scaled skin, darkening and thickening of the skin
  • Bacterial and yeast infections
  • Chronic ear infections
  • Cats can have all of the above symptoms in addition to respiratory symptoms, such as wheezing or coughing

How are allergies diagnosed?

  • Intradermal skin test
    • Tests a range of allergens
    • Requires short sedation
    • A positive result doesn’t necessarily mean the animal’s symptoms are caused by that particular allergen- your vet will need to gather more information
  • Serum allergy test (ELISA)
    • Blood test
    • No sedation needed
    • Good for older, sicker pets or cats
    • Measures specific levels of antibodies to a particular allergen

What are the treatment options?

  • Hyposensitization
    • Pet receives injections to counter the specific allergen
    • Injections are usually given every 3 days for 6 weeks
    • Owners are taught how to give the injections themselves
    • Boosters are continued once a week for life
  • Cortisone (steroids)
    • Effective in reducing symptoms
    • Can have side effects
    • Not recommended for long-term use
  • Antihistamines
    • Great for itchiness
    • Safer than steroids, but do not work as quickly
    • Some side effects
    • Some lose their effectiveness over time
  • Essential fatty acid supplements
    • Used along with other medications to help with itch relief
  • Topical therapy
    • Shampoos, conditioners, lotions, etc.
    • Used in addition to above therapies

How do I learn more?

Visit AMC’s Dermatology Service page for more information

For more information about the Usdan Institute of Animal Health Education, contact:
Jaclyn Skidmore, Director of the Usdan Institute for Animal Health Education
jackie.skidmore@amcny.org

Ear Infections in Dogs and Cats

ear infections

Yesterday I saw one of my favorite patients, a cute, red poodle named Charlie. As a baby, his bone marrow shut down for some unknown reason but ultimately recovered. Last summer and fall, he had a much more mundane problem: recurrent ear infections. Because of his chronic ear infections which would clear up with drops and then immediately relapse, I referred him to the Animal Medical Center’s dermatologist. The prescribed treatment for allergies has kept the ear infections under control. Since it is spring and the beginning of allergy season, your pet may be one of the unlucky ones to develop an ear infection secondary to allergies.

Ears are Really Skin
Because the ears are really part of the skin, dogs with allergies to substances in the environment, like pollen or dust, may have itchy skin or just have recurrent ear infections. Some dogs incessantly lick at their feet. The current theory of why ears and feet are the most commonly affected body parts stems from how dogs behave. Outdoors, your dog has his nose and head to the ground, stirring up pollen and other nasties which adhere to the face and ears; and of course, their feet tread in this same milieu. In normal dogs, the skin protects against the allergens, but in dogs with allergies, the skin barrier is in some way defective. The defect in the skin barrier allows allergens to enter the body, where they stimulate an allergic response.

Inflammation Leads to Infection
An allergic response can lead to itching, redness, and swelling which in turn changes the environment of the ears, leading to infection. Yeast and bacteria are the most common organisms identified in association with an ear infection. Typically, veterinarians wipe a cotton swab inside the ear to collect material which is then rolled on a microscope slide, stained and examined as part of the diagnostic testing. Occasionally, a sample of the discharge is submitted to the laboratory for identification of the causative organism to help treatment be as focused as possible since yeast and bacteria are treated with different medications.

Mighty Mites
Allergies are a much less common cause of feline ear infections than canine ones. Kittens, especially those raised outdoors, frequently contract an ear mite infection. These multi-legged parasites cannot be seen by the naked eye, but the little buggers can produce buckets of grainy black ear wax, clearly visible inside your cat’s ear flap. Another reason you can’t miss ear mites in your cat is the constant head shaking and ear scratching induced by their presence in the ear canal. Fortunately, a bit of black wax viewed under the microscope will readily identify mites, which are easily eradicated with ear drops.

Signs of an Ear Infection
If your pet has folded ears, you might not see the infection right away, but a bad smell coming from your pet’s head might clue you in to the problem. Head shaking, ear scratching or even shying away from a friendly pat on the head may be another clue to a brewing ear infection. If you look closely, you may notice the ear flap is swollen, red or scabby from scratching and there is a buildup of waxy or other material in the canal. If you notice any of these signs in your dog or cat, call your veterinarian’s office immediately to schedule an appointment.

Treatment of Allergies in Pets

Spring officially arrived nearly three weeks ago, but the onset of allergy season may not arrive too soon this year, given our harsh winter. But once it warms up, pollen, dust mites, fleas, grass, weeds and mold will kick off allergy season in pets.

Clinical Signs of Allergies
Does your dog rub his face along the front of your sofa or scratch incessantly? Has your cat scratched all the fur off her head and made is scabby? Are you constantly putting in ear drops or giving antibiotics to treat skin infections? All these represent clinical signs of allergies in pets.

Control Parasites
One of the top causes of canine and feline allergic skin disease stems from an allergic reaction to flea saliva. A flea bites your dog or cat, setting off an allergic reaction. This disease presents a double-whammy to your pet: discomfort from fleas crawling all over its skin and the discomfort of being itchy. Fortunately, numerous options for control of fleas are available and your choice of product can be tailored to your pet’s exact needs.

Modify the Diet
Food allergies are typically an ongoing problem, not seasonal like pollen, grass or flea saliva allergies. Veterinarians think the allergen in food is the protein source contained in the diet, but it may be other ingredients as well. The standard method for determining if food is the cause of skin disease is a food elimination trial. Elimination diets contain a limited number of ingredients and protein sources not typically found in common pet food and not previously fed to your pet. Novel protein sources include bison, herring or rabbit. Some elimination diets avoid common carbohydrate sources and include potatoes or oats, rather than corn or soy. An elimination diet requires determination on the part of the pet owner, as the skin improves slowly in response to a diet change. Patience is required to tough out a month or more of strict diet control.

Administer Immunotherapy
Immunotherapy, a medical word for allergy shots, involves specialized testing to determine whether it is pollen, dust mites, fleas, grass, weeds or mold revving up your pet’s itch-scratch pathway. Once the cause of the allergy is determined, a custom allergy vaccine can be developed for your pet. You learn to give the injections at home one to two times per week. These injections contain minute amounts of the offending antigen (pollen, dust mites, fleas, grass, weeds or mold) which trains your pet’s immune system to be tolerant of these agents.

Quell the Immune System with Drugs
A variety of drugs can be used to turn off the allergic reaction underlying the itch-scratch cycle in your pet. The most well-known, but not necessarily the most effective in pets, is antihistamines. Steroids can be very effective and rapidly reduce the clinical signs of allergies, but have unpleasant side effects, such as increasing water drinking, urination and appetite, as well as increasing the risk of infection. Another effective drug for allergy management is cyclosporine, although cost is a concern. New to the market, oclacitinib, inhibits the cells initiating the itch-scratch cycle by attacking allergies at the cellular level.

With so many options to manage pet allergies, no pet should have their summer fun spoiled by constant itching and scratching. Watch The AMC’s Dr. Mark Macina talk about managing allergies in pets.

Allergies in Dogs: 4 Treatments to Help Scratch Your Dog’s Itch

The summer of 2012 will go down in my personal history book as the summer of allergies. Not for me, but for my canine patients. I have received many frantic calls from my cancer patients’ families concerned that their beloved pet’s cancer has returned. After a check-up with me at The Animal Medical Center, I have reassured them the cancer continues to be in remission, but their allergies are way out of control.

Scratching bad

Today, the preferred term for allergies to things in the environment, like house dust mites pollen, mold, trees and grasses, fleas, and even your unsuspecting household cat, is allergic dermatitis. Allergic dermatitis is also known as atopy, allergic inhalant dermatitis, seasonal allergy, or environmental allergy. Whatever it’s called, the manifestation is red skin, “hot spots,” ear infections, recurrent skin infections and scratching like mad. The development of allergic dermatitis requires two things: a dog with a genetic predisposition to developing allergies and an allergen in the environment to incite the allergic response. Allergic dermatitis is a complicated disease and often requires complicated therapy.

Complicated cause

At least three mechanisms play a role in allergic dermatitis in dogs. First, the environmental allergen causes the release of histamine from a cell known as a mast cell, which sets off an allergic reaction. T-cells have a yin-yang effect on the immune system, both ramping up the immune system and blocking a protective effect against allergies. Finally, normal skin protects the body from invasion by allergens. Dogs suffering from allergic dermatitis likely have impaired function of the skin cells, allowing allergens access and predisposing your dog to yeast and bacterial infections.

The net effect of all this cellular hysteria: an itchy dog.

Complex treatment regimen

Given the complexities described in the pathways leading to allergic dermatitis, you should not be surprised to receive a small pharmacy’s worth of prescriptions when your dog is diagnosed with allergic dermatitis. What follows is a brief description of some of the more common medications used to treat allergic dermatitis.

  1. Although the role of histamine is limited in canine allergic dermatitis, antihistamines, if they decrease itchiness, are very safe and cost effective.
  2. Shampoos play multiple roles in the management of allergic dermatitis. Bathing your dog is soothing to the skin and decreases surface allergens, and medicated shampoos decrease surface bacteria and yeast. Hopefully, new shampoos will be developed to help augment the lost barrier function of the skin.
  3. Antibiotics and anti-yeast medications are critical in controlling secondary infections in the skin of itchy dogs. The function of deregulated T-cells can be modified by the use of immunosuppressive agents, most commonly steroids, and more recently cyclosporine.
  4. Finally, dogs can get allergy shots, a form of immunotherapy where the immune system is gradually desensitized to the offending allergen. For several of my patients, this form of treatment has dramatically improved their quality of life by decreasing their itchiness and skin and ear infections.

What a pet owner can do

If your dog is scratching, as are many of my patients, see your veterinarian. When my itchy dog patients need more specialized skill than I have to manage their allergic dermatitis, I refer them to a dermatology specialist. You can find a board certified dermatologist on the American College of Veterinary Dermatology website.

I hope one or more of the treatments I have described can help make your dog more comfortable in these waning summer months.

Spring Allergies in Dogs

Spring finally has come to New York City. I know because of the springtime changes I see. No, I don’t mean the daffodils, tulips, flowering trees or the verdant carpet of grass in Central Park , nor the return of the robins, Yankees or Mets. It is the phone calls from the owners of Willie, Coco, Willa and Roman who have noticed their dogs licking, scratching and chewing at themselves and shaking their heads due to itchy ears.

Signs of an Allergy
Dogs that are licking, scratching and chewing at themselves likely have allergies to something in the environment, a common disorder in dogs. One of the major pet insurance companies in the United States reported the top claims for 2010. The top three in dogs were all related to allergies: ear infections, skin allergies and skin infection/hotspots.

Types of Allergies
Your dog can be allergic to the same allergens you are – seasonal ones such as fleas, mold and pollen from trees, flowers and shrubs. Dogs also suffer from non-seasonal allergies to dust mites or feathers. And poor Roman has been diagnosed with being allergic to cats! This time of year we suspect seasonal allergies, but if the scratching and itching continue into the winter months, then we worry about year round allergies.

Treating Allergies
If your dog has seasonal allergies, frequent bathing with soothing shampoos and medicated rinses often help, especially after weekend romps in the park. If your dog develops a skin or ear infection as a sequel to her allergies, your veterinarian can evaluate an ear or skin swab and determine the proper medication to remedy the situation. Sometimes antihistamines or steroids are prescribed to help control the itch.

Seeking a Veterinary Dermatologist
When the allergies are present year round or are not controlled by the methods described above, a veterinary dermatologist can perform special testing to determine the allergen(s) causing the problem. Two types of allergy testing are available for dogs: a blood test and intradermal testing (the skin prick test your allergist may have used on you). The veterinary dermatologist will determine what test is best for your dog. Most dogs are allergic to more than one thing and a custom allergy vaccine can be created for them based on the test information. You give your pet small volume injections under the skin to decrease the immune system’s response to the allergen, and over time the itching, scratching and associated skin and ear infections subside.

If your dog is scratching more this spring or seems to always have an ear infection, maybe he has allergies. See your veterinarian for advice on management and follow the directions closely to avoid a serious hotspot or ear infection this spring.

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This may also be found in the “Tales from the Pet Clinic” blog on WebMD.com.

For over a century, The Animal Medical Center has been a national leader in animal health care, known for its expertise, innovation and success in providing routine, specialty and emergency medical care for companion animals. Thanks in part to the enduring generosity of donors, The AMC is also known for its outstanding teaching, research and compassionate community funds. Please help us to continue these efforts. Send your contribution to: The Animal Medical Center, 510 East 62nd Street, New York, NY 10065. For more information, visit www.amcny.org. To make an appointment, please call 212.838.7053.