Flea Allergy Dermatitis

When feeding, fleas inject saliva into the host on which they are living. Many dogs and cats are allergic to flea saliva. Even nonallergic animals will scratch due to the annoyance of flea bites. Allergic dogs itch intensely in some or all areas of the body. They are likely to be restless and uncomfortable, spending much time scratching, licking, rubbing, chewing, and even nibbling at their skin. This often leads to hair loss, scabbing, and secondary infections. In heavy infestations (or in young puppies), anemia may develop due to the loss of blood.

Most cases of flea allergy dermatitis occur in the late summer, corresponding to the peak of flea populations. Animals younger than 1 year old do not usually have flea allergy dermatitis. Usually, diagnosis is made by visual observation. Slowly parting the hair often reveals flea excrement or rapidly moving fleas. Flea excrement is reddish black, cylindrical, and pellet- or comma-shaped. Placed in water or on a damp paper towel, the excrement dissolves, producing a reddish brown color. Examination of the pet’s bedding for eggs, larvae, and excrement is also useful. The presence of fleas does not exclude another disease being at least partially responsible for the dog’s itching and skin condition. Your veterinarian may do skin testing to eliminate other causes for the itching and confirm a diagnosis of flea allergy dermatitis. Other conditions that can look like flea allergy dermatitis include respiratory allergies, food allergies, mange and other skin parasite infestations, and hair follicle infections. Flea control measures have changed

The Merck/Merial Manual for Pet Health. Copyright© 2007 by Merck & Co., Inc.,
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