Environmental allergies (atopy), flea allergies, and food allergies can wreak havoc on your dog or cat’s skin. The most common sign of an allergy is itching. When dogs and cats have an allergy, they will constantly scratch, chew, and lick their skin and paws. You may also notice some visible changes in their coat or skin. Chronic allergies can be miserable for pets and their parents.

There is a vast difference between the three types of allergies, so it is best to seek advice from your veterinarian for a plan of action. Based on what they find on exam and history, they may suggest a customized treatment plan, high quality flea prevention, or even potentially either an elimination diet or testing for environmental allergies. It is important to note that what works for one animal may not work for another. It may take time to figure out what triggers your animal’s allergies and how best to treat them. With help from your vet, you will be able to figure out what causes your pet’s allergies and how to prevent them.

Types of Allergies 

Flea allergy

It’s estimated that about 40% of all dogs are hypersensitive to flea bites. Sensitivity to flea saliva is a prevalent condition in dogs and cats. The flea will bite the animal, but the saliva injection (not the bite) causes most of the itching. The saliva of just one or two fleas can make your dog miserably itchy and uncomfortable for potentially months (even long after the fleas are gone).

In dogs and cats, a flea allergy/issue will have a very characteristic appearance. The nice thing is that because the appearance is so specific, it’s a very easy diagnosis. They will be very itchy from the middle of their back to their tail and there is often a noticeable amount of hair missing. In cats, owners are usually reluctant to agree with a flea possibility because 1) they never see any fleas on them and 2) they are inside only. Often, even for the doctor, it is hard to find fleas on a cat because they are so good at grooming that they eat all of the fleas. If they have that characteristic coat appearance, you can guarantee they have a flea issue. Cats may also develop a bad rash on their nose. Owners will also believe it’s not a possibility because they have their pet on flea prevention but there is a huge difference between flea prevention you can get from the store and what you can get from the vet.

Atopic Dermatitis

This is comparable to hay fever in humans, except your dog will itch instead of having a runny nose and sneezing (although they may deal with a little of that, as well). A large percentage of all dogs have atopic dermatitis (also known as seasonal or environmental allergies), especially in southeastern Louisiana. Atopic dermatitis can be caused by grass, pollen, ragweed, trees, weeds, mold spores, dust, and dust mite droppings.

Dogs may be exposed to these allergens by breathing them in or exposure through the skin. The most common sites that atopic dogs develop clinical signs are on are the feet (licking or chewing), the face – which they will rub against carpet or furniture, and the tummy, groin, and “armpit” areas.

Diagnosing atopy tends to involve trial and error, so the more information you provide to your veterinarian, the sooner you can solve the problem. Depending on the specific issues your dog has, a treatment plan will be put in place and may involve a combination of medications. Your dog may be dealing with a secondary bacterial or yeast infection (or both), which is a secondary issue to a compromised immune system with severe itchiness. Just keep in mind, atopy is not a disease that will ever go away – it will be something that your dog will deal with lifelong.

Food Allergies

Did you know that food allergies account for about 10% of allergies in pets? Owners are often fooled into buying a particular brand of food because it’s grain-free or the person at the feedstore recommended it. In reality, protein is the main food allergy culprit, usually chicken or beef. This may be surprising to you since most dog owners think their dogs are the ultimate carnivores.  Dogs may also be allergic to carbohydrates, preservatives, or food dyes.

Clinical signs of a food allergy are highly variable. Nearly half of the dogs who suffer from food allergies also exhibit other hypersensitivities, making the food allergy diagnosis difficult. The skin, gastrointestinal tract, respiratory tract, central nervous system, or any combination of these may be affected. When the skin is involved, there is a generalized itchiness all over the body, specifically, the rear end will be very irritated. They may also deal with digestive issues, not just skin.

Food hypersensitivity can begin at any age, even late in the dog’s life. So, there are many reasons your dog would be licking or scratching themselves. Food allergy diagnosis is only done when atopy has been ruled out and the only way to do it is through what’s called a food trial. A food trial is feeding your pet a PRESCRIPTION food allergy diet for a minimum of 8 weeks.

Overlapping Symptoms

Since so many symptoms overlap regarding allergies, it is best to check with your veterinarian instead of assuming which one (i.e., stay off of Google!).

Environmental and food allergies may present similar symptoms, including:

• Itchy, flaky skin
• Ear infections and/or stinky ears
• Hair loss or bald patches
• Excessive licking and biting of the paws
• Face rubbing
• Sneezing
• Scratching
• Eye discharge
• Respiratory problems
• Hives

If your vet has done everything to rule out atopy or food allergy, they then may suggest you bring your pet to a dermatologist. The extra testing that they will do is what’s called an intradermal skin test. They will inject about 20 different small areas on your dog’s skin, each including a different allergen. Depending on what spots swell (indication a reaction to that allergen), the dermatologist will formulate a customized allergy medication specifically for your dog. Also, while some vets recommend it, bloodwork for allergies is not reliable.

What You Can Do

Keeping your animal on vet-recommended flea preventative is the first step (only if we’re sure fleas are the issue).

You should only be changing your dog’s diet to rule out food allergies under your veterinarian’s supervision. Randomly changing your dog’s diet can do more harm than good, and a proper “hypoallergenic” diet should be obtained from your veterinarian. Over-the-counter diets that claim to be ‘hypoallergenic’ or ‘novel protein’ do not have the same quality control as veterinary prescription diets due to manufacturing cross-contamination.

It is also important to note that allergies are not the only reason that dogs itch. Itching may be caused by other factors such as a drug reaction, or a disease like pancreatic, liver, or renal disease. This is why it is essential to visit your veterinarian. That way, you can rule out any underlying conditions before you solve your pet’s allergic reactions.