Is My Dog Allergic to Fleas?

September 14, 2022

Hearing your pet diagnosed as having fleas can understandably elicit a range of reactions from disgust to disbelief. You might wonder how this could possibly happen when you take such great care of your pet or it never goes outside. It is equally understandable not to believe the diagnosis since most people do not actually see fleas on their pet.  An even more surprising thing to hear from your vet is that your pet is allergic to flea saliva.

The truth is, fleas are very common to see year-round in Florida since we do not have drastic seasonal changes. Wildlife and feral cat populations that harbor fleas are abundant in Florida and live in close proximity to people and pets. Even if your pet never goes outside, they are still at risk of picking up fleas if a flea hitches a ride in your house on you or something you are bringing inside. Even more shocking is that once fleas are established in your home, it can take weeks to months to completely clear the infestation. Flea eggs are resilient, impossible to see and can hatch over a period of three months. For pets with an allergy to fleas, this can mean months of itching and being uncomfortable.

Most pets with fleas will exhibit some signs of itching and discomfort however, in flea allergic pets, these signs may be severe. Dogs with flea allergies will scratch and chew incessantly at their hind end and back legs. Cats will often over groom their lower back, abdomen and hind legs. In both cases, the longer it goes undiagnosed, the more likely the pet will become bald in the hind end giving them the appearance of wearing pants. Pets with severe flea allergies do not need to be completely infested with fleas to show signs of intense itching and overgrooming. In a lot of cases the bites of only a few fleas can trigger an allergic reaction and you may never see the flea if your pet has already ingested it while chewing themselves.

Treatment of flea allergies can involve a combination of things depending on the severity of the case. Topical or oral antibiotics may be required to treat any secondary skin infection that was caused from scratching. Medications to block the urge to itch are often used to temporarily provide relief such as steroids, antihistamines or Apoquel. The most important goal of treatment will be focused around ridding the pet and its environment of fleas. This will involve flea treatment to kill the adult fleas and frequent cleaning of the house to remove all the microscopic flea eggs.

For flea allergic pets, the best treatment is prevention. Once diagnosed with a flea allergy, it is extremely important to stay on a strict monthly regimen of an oral or topical flea preventative. It is also imperative that every pet in the house stay on monthly flea prevention even if they never go outside as any unprotected pet in the house can become a host and breeding ground for fleas. In extreme cases, some flea allergic pets may need to be on a combination of oral and topical flea preventatives if prescribed by the vet. The best products are oral preventatives such as Simparica Trio, Bravecto and Nexgard. Some topical preventatives may work as well such as Bravecto for cats. In most cases, over the counter flea preventatives such as Frontline are not very effective against fleas in Florida and some of the generic brands can have unwanted side effects on your pet. Please ask a veterinarian before applying any flea preventative to your pet. If you think your pet may be experiencing a flea allergy, talk with a veterinarian to develop a thorough treatment and prevention plan that works for you and your pet.