Itching and Allergies

It’s a beautiful morning on Mount Rushmore. You’re roller skating on Thomas Jefferson’s nose with Johnny Depp, Ringo Starr and your late uncle Bernie. Johnny is about to execute a perfect triple-axel when suddenly everything starts shaking and you sit up in bed. Is it an earthquake?! No, it’s Buttercup, scratching like a maniac and shaking the bed. AGAIN. That’s the third time this week! You can banish her from the bedroom and go back to sleep, but that won’t solve her problem.

In Southern California, the number-one reason for veterinary visits is an itchy pet. Unfortunately there are so many causes for itching that the problem is often not immediately apparent. It can be difficult to determine the source of the irritation, which gets frustrating for owners and vets alike. Not to mention poor Buttercup, who gets carsick on the way to the vet and is STILL itchy.

This article will touch on the most common reasons for itching in pets, but cannot cover them all by any means. The following is meant as a guideline and not as a diagnosis or treatment plan for your pet. If your pet is scratching, your best course of action is to seek veterinary care before attempting any treatment yourself.


Fleas and flea myths

I often encounter resistance from clients when I suspect a flea-related dermatitis, even though it is the most easily treated cause for itching. There’s a weird stigma attached to fleas, but I’m not sure where it came from – having a flea problem does not indicate uncleanliness or laziness. Fleas are nasty little opportunists. If you’re not using effective flea control, they’ll move in regardless of how often you bathe Buttercup or how frequently you clean your house.
Here are a few common flea-related myths we hear all the time:

  1. “Buttercup is indoor only. She can’t have fleas.” Wrong. Like I said, fleas are opportunists. Wild animals like squirrels, opossums and raccoons all carry fleas, and your house is just a hop away for an errant parasite. Once that flea finds its way to Buttercup, all it has to do is lay its eggs and you’ve got an infestation on your hands.

  2. “Well, I don’t have carpeting so there’s nowhere for the eggs to hatch.” Wrong again. Flea eggs fall off the pet and into the environment , but they don’t need carpeting to survive. They can hide in tiny cracks in wood or tile flooring, not to mention in furniture and bedding (including your bed). And vacuuming won’t get rid of them because their sticky coating allows them to cling to whatever surface they find.

  3. “OK, but fleas love me. If Buttercup had fleas, I’d be getting bit all the time.” Not necessarily. Although fleas will bite people, they prefer to take their meals from a dog or cat. If Buttercup is around, the fleas will bite her preferentially. Think of it this way: to a flea, Buttercup is filet mignon. You’re Spam.

  4. “Fine, there might be fleas during the summer, but not in the fall and winter.” Don’t kid yourself! It’s not like fleas check the calendar and immediately drop dead the minute November arrives. This is Southern California. It was 83 degrees in Huntington Beach the second week of January this year. If it’s not cold enough to snow, it’s not cold enough to kill fleas.

  5. “Well, I never/hardly ever see fleas, so that’s not the problem.” I wish it were that easy. Unfortunately, a pet with a severe flea allergy can have a major reaction to just one flea bite. Remember, it only takes one flea to create a major infestation. Even if you don’t see them, they might be there. If you do see one, you have hundreds.

If you are currently using flea control and are still suspect your pet has fleas, you might need to change your flea product or try attacking the fleas at two points in their life cycle. Most flea control products are adulticides, meaning they only kill the adult fleas. However, flea eggs hatch in the environment, which means a whole new crop of bugs is waiting to feast on Buttercup. We recommend using an adulticide plus a product like Program, which makes flea eggs nonviable. You sometimes also need the extra boost of an environmental agent to kill all the eggs and larvae. Contact your veterinarian for advice on the most effective flea control products.

Remember, fleas are nothing to be embarrassed about. If it makes you feel any better, my own dog had fleas last year. I was thrilled when her itching turned out to be something so simple! I’d been afraid I was going to have to spend hundreds of dollars on fancy medications and dermatology referrals. Given the choice between the two, I’ll take fleas.

Other parasites

There are several parasites besides fleas that can cause itching in pets. Certain types of mites such as demodex and scabies cause intense itching and can only be diagnosed with microscopic examination of a skin sample. Ringworm is another relatively common skin infection and can be diagnosed with a culture. These types of parasites usually cause localized hair loss and irritation, and in the case of ringworm (which is actually a fungus, not a worm), you may see a raised, red, ring-shaped spot at the itchy area. Fortunately, these kinds of infections are highly treatable, so if you think your pet may have a parasite, take him to your vet immediately.


A food allergy is the second most easily treated cause for itching (but that doesn’t mean it’s easy). Many pets develop food allergies even if they’ve been eating the same food for years. Food allergies can cause severe generalized itching, chronic ear infections (otitis), and sometimes concurrent GI signs like vomiting and diarrhea. Unfortunately, just switching pet food brands usually isn’t enough because pets tend to be reacting to a specific protein in the food. Changing from Iam’s to Blue Buffalo won’t help if they both contain the same ingredient that causes Buttercup’s itching.

Despite the popularity of grain-free pet foods, grain allergies in pets is fairly uncommon. Most pets with food allergies are actually reacting to the protein source in the food. To determine if this is the case, we place the animal on either a hydrolyzed protein diet (one in which the protein is broken down so the pet is less likely to react to it) or a novel protein diet (a diet in which the protein source is one your pet has never eaten before; often venison, rabbit or duck). At the end of the eight to twelve week trial period, we challenge the pet with her old food. If her itching worsens, we can assume a food allergy is at least partially responsible for her problem.

It can take a couple of months on the trial diet to see a major improvement, so don’t get frustrated if you haven’t seen a big change in the first few weeks. Also, if you do embark on a trial diet, be prepared to administer some tough love – the key to a successful trial is feeding ONLY the new food. That means no treats, no people food, not even any flavored medications. If your pet eats any other food during the trial period and has a reaction to it, we won’t know if the new diet is working. And remember, these are prescription diets and they aren’t cheap, so sneaking Buttercup that piece of bacon won’t do her or your wallet any favors.

Atopy is a fancy word for hypersensitivity to allergens. Essentially, an atopic pet is allergic to life. That’s a very simple way to describe a very complicated problem, but it’s fairly accurate since there are so many allergens that can contribute to the problem. An atopic animal could react to anything from dust and dust mites to pollen or plants. These allergies are most commonly expressed as itching, chewing, biting, or scratching at the paws, legs, armpits and face, but the itching can extend over the entire body and there may also be chronic ear infections. All this chewing and scratching introduces bacterial and yeast infections, and before you know it your best friend is a miserable, irritable, stinky mess.

Before a pet is diagnosed with atopy, other causes such as parasites, food allergies and endocrine diseases must be ruled out. Your vet may want to run several diagnostic tests such as skin scrapings and blood panels to ensure the problem is not caused by an underlying disease. Once these other differentials have been ruled out, you have several options for treatment. Antibiotics and anti-yeast medications are commonly used for the secondary infections. Serologic and intradermal testing can determine the specific allergens causing the reaction, and a dermatologist can formulate a plan for antigen injections. Other treatments such as antihistamines, anti-inflammatories (steroids), and immunosuppressive drugs can be helpful as well.

Atopy is a frustrating problem because it takes a lot of tests to diagnose, and while it is treatable, it is not curable. However, with the proper treatment we can get the problem down to a manageable level and return your best friend to his normal happy (and significantly less stinky) state.

This was just an overview of the most common causes for allergies in pets. There are other reasons a pet may be itchy, so it’s important to contact your vet if your dog or cat is scratching. Itchy pets don’t have to suffer, and you shouldn’t have to miss Johnny’s triple axel one more night.

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