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Itching to Learn about Allergies?

The itchy dog or cat; by far the most common issue I’ve seen over the years as a veterinarian, so let’s take a look at the reasons behind the itching and how we can best treat these animals.

First, consider all the reasons why your dog or cat could be itchy:

  • Atopy: pollen allergies that are seasonal and makes them itch at their ears, face, groin, armpits, feet or under their tail.
  • Food allergy: non-seasonal itch of ears, feet, or under their tail.
  • Parasites: mange, a non-seasonal itch anywhere on the body; and fleas, which makes them itchy over the tail head.
  • Contact allergy: itchy where the animal comes in contact with something, or hypersensitivities to their own normal skin inhabitants
    (yeast and bacteria).

The most important thing I can do is obtain a really good history from the owner about this itchy issue.

Why? Because in order to treat the current problem and anticipate how we are going to prevent further problems, I need to know the following information:


  • The current age of the animal. Younger animals are more prone to things such as mange, versus an older animal. Older animals are more prone to inhalant and food allergies.
  • Where does the animal itch? Flea allergies, for instance, are much more likely to cause itching above the tail head versus, let’s say, food allergies in cats that cause them to itch between the eyes and ears. Food allergies and inhalant allergies will cause itching in many of the same spots. Inhalant allergies, or “atopy”, are primarily due to pollen. Inhalant allergies cause certain types of cells to become activated and release substances called histamines that lead to itching. These histamine-containing cells are primarily located in the skin of animals; in humans, histamine releasing cells are mainly located in the respiratory tract, nose and eyes.
  • Which came first, the itch or the scab? Most of these itchy dogs will present with a concurrent bacterial infection of the skin; knowing which arrived first helps immensely but it requires a very observant owner. An itch can lead to skin infection, but a skin infection can also lead to an itch. Knowing which came first is monumental in that primary bacterial infections (scabs first) are treated with antibiotics alone when caught early, whereas the atopy (itching first) dog needs steroids, antihistamines and fatty acids to treat and prevent their itching. Knowing this difference will help anticipate which preventative measures will be most likely to succeed.
  • When did the itching start? Seasonality of the itch is the key to diagnosing an itchy dog or cat. The inhalant allergies from pollen will occur during months when things bloom – easy to realize when you live in the north and have snow that covers the ground for 6 months of the year, but a little more tricky when you don’t have winter. Winter itching only would make me consider household dust mites, molds, etc. as a culprit. If we have an animal with a year-round, non-seasonal itch, then we start to consider the following: food allergies, hypothyroidism, Cushing’s disease, sensitivities to their own skin inhabitants such as yeast or staph bacteria, and parasites.
  • scratch

  • How severe is the itch? Severe itching that wakes the owner up at night always makes me consider mange. There are two types of mange: 1) Demodectic mange which dogs under one year of age get, and 2) Sarcoptic mange, which is more common with older dogs and occasionally cats. Demodectic mange will present with a patchy hair loss pattern and little or no itching. Sarcoptic mange will present with a dog that almost never stops itching and has hair loss due to scratching. Both are diagnosed with skin scrapings and can be treated by your veterinarian successfully.
  • Itching that doesn’t wake the owner up still is valid, and I still will do a skin scraping to rule out mange. The level of medication to treat the itch will be dictated by what we find to be the cause of the problem if we are confident that we understand it.
  • What medications have been tried, and what was the result? This can tell me a ton. For instance, food allergies don’t typically respond well to steroids while atopy cases do. Parasite issues often are not helped at all, and can actually worsen with the use of steroids, and primary cases of staph bacteria hypersensitivity will improve with antibiotic use alone.
  • scratch

  • What food changes have been tried? For many years, my only option with suspected food allergies was the food trial. Dogs and cats, if allergic to their food, are actually allergic to the proteins in the food – sometimes many proteins or just one protein. So to do a proper food trial, we change the dog or cat to a food with as few proteins as possible and hopefully new proteins that they have never been fed before. All other food items need to be eliminated and a minimum of two months is needed to judge whether the food change has made a difference. Two months may seem like a long time, but it can take that long for the animal to expel all previous food allergens from their former diet. This sure can be a drag to do correctly, and few clients can make the two months. The good news is there are two other options in lieu of the food trial that can be done: 1) Blood tests that detect certain antibodies that are used to correlate exact proteins that lead to allergies or 2) A skin injection test to find those protein culprits. I personally have had pretty good luck with the food allergy blood tests and use them regularly.
  • Has there been any blood work done? Hypothyroidism is a very real problem in certain breeds and can lead to many chronic skin and non-skin issues. Several common symptoms are the itchy dog or a dog that has a thin haircoat. Never discount hypothyroidism with a long-term itch that just doesn’t respond well to treatment or continually recurs. Often on first presentation I may test a dog that is itchy for a long period of time, has hair loss and has a “thin skin” feel to them. Easily treated with thyroid supplementation, it is a straight-forward fix in most instances. Routine blood work would also include liver and kidney function tests, urinalysis and complete blood counts. This could help rule out Cushing’s disease, which in a nutshell is an endocrine problem that leads to excessive self-creation of steroids on the part of the animal. These excessive steroids will then cause the immune system to not work well and allow simple scrapes to turn into big infections – and thus an itch. Diagnosed by further testing, Cushing’s can be successfully treated by either trilostane or mitotane. Determining the cause of the itch is not insurmountable. However, it does take patience, a very thorough history, and more patience. One thing to remember with skin issues is that they can require a lengthy game of CSI to fix the problem – it might take some time on the part of the vet and client to solve the riddle. Quick fixes are usually just that; a short relief for your pet before the itching recurs. If we want to do our best to eliminate and prevent recurrence of that dreaded itch, we need to take our time and do it right.

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rose    09.22.11

very informative
Included with fleas should be flies and mosquitos. For outdoor dogs mosquitos can bite by the hundreds and you don’t notice them until you look. If a cold snap releives the itch in outdoor dogs and they have their spot on treatments suspect the mosquitos.
I would like to see a safe leave on treatment for mosquitos. The few that make the claim to prevent mosquitos are not effective and mosquitos can kill with heartworm.

Mary LaPorte    09.22.11

My GSD was spayed in August 09. One year letter she developed a staph infection after swimming in a pond. since then she has had on going hot spots and staph infections. Could it be hormonally related? How long do you keep a dog on antibiots? The infections clear up after two weeks, I keep her on one week more, but wonder if that is long enough.

Do you ever put dogs on Hormone Replacement Therapy? I regret spaaying her.

By the way, I am from Escanaba, live in the Lansing area now. Gret Food. I get it at Mason Elevator and rotate with a raw diet.

Marianne Galligan    09.22.11

Hello Dr. Tim. This was sent to me from Lark Hytinen….as I have two of their Newfies here. One of them, a 6 yr old Landseer neutered male, has been having skin problems since approximately a year or two years old. Earlier this Late Winter/Early Spring (Feb/March), his itching was SO incredibly bad, that he needed sutures to close a wound that he caused himself – due to his extreme itching. I had to bring him to the emergency vet as this happened on a Sunday night. He was shaved down, put on antibiotics, prednisone, as well as thyroid meds. His thyroid level was reading extremely minimal! The antibiotics and pred seemed to help him tremendously. His skin cleared up. Within this past month, we are back to the beginning. I have been keeping Lark updated on him from the getgo. Is there anything that you can help me with for Snuffy? (Landseer Newfie). Something you can send me? I am so desperate to help him. Many thanks!

Lois Forrester    09.22.11

Hi Doc,
I bought a bag of your food yesterday for my pooches when I picked up Chloe (thanks by the way)….I read the brochure and saw you had a website so I thought i would check it out. I immediately read this article on “itching” as our Tinkerbelle still suffers from that…she itches around her ears and muzzle…she does not have scabs…seems to itch more in the summer, but her scratching is very disturbing as her little foot keeps thumping against the floor. We have used the special shampoo from you and does seem to help the first day after. it also helps when we put the drops in her ears…but what you said about diet makes so much sense…so I am hoping the new food with show some improvement if not….we will bring her in so you can run some tests. Thanks for the website…very informative. Hope your day is blessed. Lois

Shannon Fillion    09.22.11

Hello Dr. Tim,
I am writting you as I have come accross your dog food brand via dog food chat website. The issue i am having is that my dog Duffy (german sheppard/collie cross) has been diagnosed by our vet to have generalized Demodectic mange. Since she is collie we had to switch to a special brand of medication although I am aware that there is an underlying issue with her immune system to cause this situation. I have been doing much research on the disease and understand that it is very difficult to cure. I was hoping you could provide me with some greater insight on other options to help with the itchiness she is having. It is so sad to see your puppy (turning 1 yr on Dec. 29) to be itching so badly she is creating open wounds on herself. It started with her face and healed to a point but is now getting progressively worse once again this time more in the paw region and around her left eye.
Thank you

I think it's his food that makes Montana itch so much    09.22.11

[…] in 10 Posts Here is a link to an article about diagnosing allergies. Hope it helps. Premium All Natural Pet Food | Dr. Tim's Reply With […]

Corey Cromell-Merrick    09.22.11

What type of antihistimines can be used for dogs? I have 2 shihtzu/bischon mixes and they both itch like crazy in the fall, so I think it’s atopy related. And what dosage? They both weigh approx 20 pounds. Thank you!

admin    09.22.11

Dose of benedryl is typically 1 mg per lb twice a day. Atopy is a tough one but also remember you can use topical shampoos to remove the pollen to help diminish the itch.

au meilleur prix Adidas Homme    09.22.11

Admiring the commitment you put into your website and in depth information you present. It’s good to come across a blog every once in a while that isn’t the same out of date rehashed material. Excellent read! I’ve saved your site and I’m including your RSS feeds to my Google account.

admin    09.22.11

Thank you!

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