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Flea Allergies and Your Pet

By Colleen Williams
September 21, 2018 • 2 min. read
dog scratching fleas

Fleas are a common frustration for both cats and dogs. As if these little suckers (literally) weren’t bad enough, their saliva is the most common cause of a specific skin allergy called “Flea Dermatitis.”

What is Flea Dermatitis?

Flea dermatitis is a very itchy disease, which often leads to the development of other skin infections such as acute moist dermatitis (hot spots) and Alopecia (hair loss). It is caused by the saliva of fleas.

Fleas are bloodsucking insects with a life span of 6 to 12 months depending on their environment. They are susceptible to the cold, so all four life-cycles stages (egg, larva pupa and adult) cannot survive exposure to temperatures less than 37.4 degrees F. This is why it seems like flea dermatitis is a seasonal condition, which peaks during the summer and fall. Once the flea reaches adulthood it must find a host almost immediately to begin feeding. You see, they need blood to reproduce. Once they reproduce, female fleas can lay up to 40-50 eggs per day for over 100 days.

Even with the advances in flea control, flea bite allergies or hypersensitivity is the most common dermatologic disease of domestic cats and dogs. When a flea is feeding, it injects a variety of histamine-like compounds (fun fact: it’s the same thing that makes you itch from a mosquito bite). It’s these compounds that cause the skin irritation and allergies.


So, how do you know if your pet is allergic to fleas? Here are some signs to watch for:

  1. Severe itching, chewing and licking (especially towards the tail)
  2. Skin lesions (blotchy patches or infections on their skin)
  3. Presence of fleas or flea “dirt” (reddish-black powdery substance on the skin)

Treatment & Prevention

See your veterinarian promptly for treatment of fleas, dermatitis, and skin lesions. Depending upon the skin infection, they may treat with antibiotics or allergy injections. You may be required to bring in a fecal sample to test for further parasites – unfortunately, tapeworms can hitch a ride with fleas, so it’s important to be thorough in checking.

Preventing flea infestation and allergies is so much easier nowadays than in the past. Chat with your vet about the appropriate treatment going forward. It can be an ingestible tablet taken every month, annual shots, or other solutions to curb parasites. Only use the species-appropriate medicine on your cat or dog.

If your pet and home are recovering from a flea infestation, you probably have your work cut out for you. Check in with a local exterminator and be diligent (for environmentally-friendly resources, start here).

The content is not intended to be a substitute for professional veterinarian advice, diagnosis, or treatment. Always seek the advice of your veterinarian or other qualified health provider with any questions you may have regarding a medical diagnosis, condition, or treatment options.

Flea management is part of preventative measures pet parents take without health insurance, however if you have an allergy or infestation on your paws, you will need some extra help! By enrolling your dog early, conditions and illnesses like parasite infection treatments will be covered up to 90% by your Healthy Paws dog insurance. Find out more by getting a free quote.

colleen williams
By Colleen Williams

Over the past decade, Colleen has written about health, wellness, beauty, and even pets for The New York Times, The Cut, Refinery29, xoVain, Healthy Paws Pet Insurance, and Seattle Met Magazine, as well as many beauty brands. She has a BFA in Art History from the University of New Mexico and an AAS in Fashion Design from Parsons School of Design in New York.

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