Flea Allergy Dermatitis
By Emily Hoppmann, DVM
According to the Companion Animal Parasite Council (CAPC), flea allergy dermatitis (FAD) is extremely common in pets and accounts for about 50 percent of all canine and feline dermatological (skin) cases reported to veterinarians. Some clinical signs you may see are scratching around the tail base, rear, and groin in dogs, and scratching or crusty bumps around your cat’s neck. Cats with FAD may also lick constantly, often to the point of exposing bare skin and causing skin lesions. Live fleas living on your pet are not always present with FAD, and just because you don’t see a flea doesn’t mean they aren’t there (they do a very good job at not being spotted!). This is especially true with cats because they are such good groomers that they often will ingest a flea before you ever see it (this can cause your pet to develop tapeworms, which can look like small grains of rice, and will need to be treated with specific medication). At your veterinary appointment, a special comb can be used to try to better detect fleas and their waste. However, even with a thorough examination and the use of a flea comb there may not be visible evidence of fleas since fleas are fast, pets are good groomers and may remove them through grooming, and if your pet is on a flea prevention the flea may have just had enough time to bite before it died and fell off your pet. Unfortunately, with flea allergy dermatitis all it takes is one bite to cause a chain reaction in your pet that can result in inflammation, itching, and sores on the skin.
Most of the more popular parasite preventives from your veterinarian’s office work great for the average pet, particularly when used year-round, but they are not magic. When a flea jumps on your pet, the preventive doesn’t kill it instantly- there’s always a bit of delay. If your pet suffers from FAD, a few bites over time can result in hours of scratching or licking. Over-the-counter flea control products are not as reliable or as effective as the products you can get from your veterinarian. Some are even too potent, which can make them toxic to pets, especially if administered incorrectly or applied to a young, underweight, or sick animal. Also, there are some dog products that are fatal if administered or applied to cats. Prescription flea control agents have been extensively tested and approved by the FDA to determine their safety and efficacy. Also, everyone working at Elgin Veterinary Hospital uses the products we carry on our own pets because we trust them and would never prescribe any products for one of our patients that we would not personally use. As an added bonus, since we all use these products, we can help answer any questions you may have about the products or their application or administration. A veterinarian can prescribe the best product for your pet based on his individual needs and his lifestyle (does he swim? hunt rodents?) and show you exactly how to apply it. Many flea products are combined with agents that control other parasites as well, which help to protect your pet from additional diseases- some of which can be transmitted to you. One of the most common mistakes made is not giving year-round flea prevention to all pets in the household. If a pet is exposed to fleas intermittently due to flea prevention not being used every month, it can result in a pet being more likely to develop flea allergy dermatitis, which leads to itchiness, skin lesions, and hair loss (most often affecting the back half of a dog, closest to the tail, and around the neck of cats). Also, just a few fleas can turn into a massive infestation in a matter of days and once there are that many fleas in your environment it is even more difficult to get rid of all of the fleas. Additionally, the outside and inside of your home will need to be treated for fleas, as well as all of your pets. We carry products that are safe to use around your pets for your yard, specific areas outside that are more likely to harbor fleas (such as under porches or in shady spots in the yard), and for your carpets. Keep in mind the adult fleas that you are seeing are less than 5% of the flea population (the rest being the flea eggs and immature fleas, which will all become adult fleas if not addressed).
Not all pets are affected with flea allergy dermatitis, though any pet is at risk of developing the disease, so how a pet reacts to a flea bite will vary a great deal depending on how sensitive they are to flea bites and if they are suffering from any other diseases (such as atopy, also known as environmental allergies). Therefore, even if you’ve administered the same parasite preventives to all of your pets and they all spend the same amount of time outdoors, one might spend all day scratching his itchy coat while the other remains relatively unaffected depending on each individuals specific allergies (flea allergies, environmental allergies, food allergies, or a combination of different types of allergies all affecting one pet). It is important to make sure you are treating all of the pets in your household – especially all of your cats, whether indoor or outdoor pets, and even your small mammals (such as guinea pigs, ferrets, rabbits, etc). We recommend this due to the fact that if you only treat the pet that’s scratching and has fleas, he’s likely to be reinfested by other pets in the house that also have fleas but aren’t giving you the same itchy signals.
Your pets should be on flea preventative year-round, as fleas can thrive any time of the year in warm, humid areas like South Carolina! Not to mention, fleas don’t just nest outdoors; other pets can carry them into the house or they could sneak in on you or other humans. This means that even indoor-only pets can suffer from FAD. As long as fleas have a warm place to thrive and a delicious host to snack on, they pose a threat to your pets. We are here to help with advice on what year-round protection is best for your pet and to help you manage your pet’s flea allergies and the skin issues that come with having flea allergic dermatitis. Unfortunately, most pets that suffer from one type of allergy are also affected by other allergies and allergies are one disease that tends to get worse as a patient gets older. However, we have great ways to help manage all types of allergies and together we can keep your pet happy and healthy!