Wait…my dog has fleas?!

Summer is upon us, and that means more pets are arriving to the animal hospital with allergies and corresponding clinical signs.  Oftentimes, their itchy skin and hair loss is related to fleas. These small parasites are frequently found outdoors and can jump on your dog while he or she is sunbathing, taking a walk, or playing ball. An allergic reaction to the saliva can occur in sensitive dogs when a flea bites, leading to intense itching, hair loss, and inflamed skin. This can be incredibly uncomfortable!

If your dog is experiencing itchy skin or losing hair, it is best to see a veterinarian for a thorough physical exam. A flea comb will be used to identify any live fleas or flea dirt (feces of fleas). The most common distribution of hair loss and inflamed skin secondary to flea allergies is on the rear end near the tail base and down the hind legs.  Absence of fleas or flea dirt does not necessarily rule out flea allergy dermatitis. When your dog goes outside, a flea can still jump on, bite, and trigger a reaction. However, the flea will not stick around and cause additional issues if your dog is current on monthly prevention.

Flea prevention is essential year-round to prevent infestations and these secondary signs in your dog. Products that work to kill fleas and ticks rather than repel them are preferred. A couple products in this category include Bravecto or Credelio. In addition, using a household cleaner specifically formulated for fleas will help eliminate any infestation present within your dog’s home environment that can wreak havoc. This is an essential step in resolving the issue. Be sure any other pets in your household are also up to date on flea prevention! Fleas can be difficult to treat due to their extended life cycle. However, this is a treatable condition with a good prognosis. For dogs that are particularly itchy, anti-histamines or steroids can be given to provide relief while any fleas are being eliminated.

Common Causes of Skin Allergies in Pets

In my previous post, I discussed the link between allergies and skin issues, like hair loss and itchiness. In this post, I wanted to dive a little deeper into this topic. So what are the possible allergic causes that could be making your furry friend downright uncomfortable? Below are three of the most common causes of allergic skin disease in pets.


The most common pet allergy is caused by fleas. Fleas are parasites that feed on your pet and their saliva can trigger an allergic reaction, resulting in hair loss, redness, and intense itching. We will typically see the hairless regions near the base of the tail in dogs and cats. Cats will sometimes experience hair loss around their chin as well. If your veterinarian suspects a flea allergy, he or she will check for evidence of live fleas and flea dirt.Your veterinarian will be able to make recommendations as far as an effective topical or oral flea preventative product as well as ways to rid the environment of fleas and their larvae. It can unfortunately take several months to resolve a flea infestation.


Another allergy we commonly see in pets is environmental. This is medically referred to as atopic dermatitis. These allergies are very similar to what we, as people, experience during different seasons. Something in the environment, whether it is grass, pollen, dust, etc, causes your pet to become itchy after multiple exposures. We usually see hairless regions or redness on the paws and inguinal regions since these are the most likely areas allergens touch when your pet is walking or laying down. As you can imagine, these allergies are a little more difficult to conquer. However, if further testing beyond your primary care veterinarian is required, he or she can refer your pet to a dermatologist who is well-equipped to perform specific allergen testing.


Some pets also develop food allergies. I can remember several occasions when I have had clients say, “..but he/she has been on the same food for years and hasn’t had these skin issues until now!” I had to explain that this is actually how a food allergy develops. Your pet is on the same diet for a long time and then suddenly (or so it seems!) develops an allergy to it. It seems counter-intuitive, but these allergies develop from repeat exposure over time as the body becomes sensitized to a certain component of the food. Typically the allergic component is the protein. Resolving a food allergy involves strict diet trials over several months. Recurrent ear infections can also point towards possible underlying food allergies.

As always, if you notice changes to your pet’s skin or coat, it is best to schedule a veterinary visit to get to the bottom of it!

Overview of Pet Skin Issues

A large portion of the questions I receive from people looking for pet advice are about skin issues. Hair loss, itching, scaly skin, redness… the list goes on! The truth is skin issues can cause frustration in pet parents because they can be difficult to resolve. This is because each pet is different and there is a vast array of underlying issues that could be playing a role. I’ll just touch on a few here.

When thinking about skin issues, it is important to look at the full picture. Have there been any recent changes in your pet’s environment? Is your pet current on flea and tick prevention? Has your pet been experiencing increased thirst, changes in weight, more frequent urination, or lethargy? What kind of diet is your pet being fed? These are just a few of the questions that are important during a patient’s exam to narrow down the cause.

Many endocrine diseases can actually outwardly manifest as alopecia (hair loss) or abnormal coat. Hypothyroidism and Cushing’s Disease are a couple examples we commonly see in dogs that can be associated with changes in skin or coat. Most of the time these endocrine diseases are diagnosed based on the distribution of skin abnormalities, by understanding patient history and other clinical signs, and through diagnostic testing.

When a pet is experiencing scratching and itchy skin, allergies are at the top of the list. Allergies are usually caused from fleas, the environment, or diet. These can be a little more tricky to diagnose! Other parasites, such as mites, can also result in intense itching and can be easily ruled in or out by looking at a skin scrape under the microscope.

Of course, skin issues can be a result of an infection, such as bacteria or yeast overgrowth as well. These most commonly cause dermatitis secondary to an underlying issue that allows the bacteria or yeast to proliferate.

With a good patient history, physical exam, and diagnostic testing, your veterinarian can work with you to determine the underlying cause and best course of treatment to make your pet happy and healthy again!

If you’d like to learn more about allergic skin disease, please check here!