Flea Allergy Dermatitis

  • Also called:
  • Flea allergy
  • FAD
  • Flea Bite Dermatitis
  • Flea Bite Hypersensitivity

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Flea Allergy Dermatitis
Flea hypersensitivity

What is flea allergy dermatitis?

Flea allergy dermatitis is a condition that affects both cats and dogs. It is characterized by severe, prolonged itching in both, and often incessant grooming in cats. It can result from very minimal and intermittent exposure to fleas. Because fleas can live year-round, we see cases of flea allergy dermatitis at all times of the year.

What does flea allergy dermatitis look like?

The skin condition looks a bit different in dogs and cats. Dogs tend to show hair loss, skin thickening, redness, and sometimes “hotspots” over the rump and tail head. The dermatitis may extend to their thighs and abdominal area. Cats may have normal-looking skin with hair loss due to excessive licking, usually over the back. Some also develop tiny red crusts over the back.

Why does flea allergy dermatitis develop?

It occurs in pets that develop a hypersensitivity (allergy) to flea saliva. When these pets are bitten by a flea, the itching that results from the injection of saliva is much more severe and prolonged than what “normal” pets exhibit. While some dogs and cats can easily tolerate a moderate number of flea bites each day, flea-allergic pets do not tolerate even one! Unfortunately, when fleas emerge from their cocoons and jump on a new host, they bite almost immediately. An effective flea repellent has not been developed. So when it comes to choosing flea products, killing them before they bite is not a realistic goal. Significantly reducing the number of flea bites is.

How is flea allergy dermatitis diagnosed?

The diagnosis is made on the basis of clinical appearance. If we find fleas, or flea “dirt”, we can be certain of flea exposure. In many cases, only the skin lesions are seen because the flea bites can be so intermittent. Flea-allergic cats and dogs are particularly effective at removing fleas from their skin by licking and biting.

How is flea allergy dermatitis treated?

The most important part of treatment is reducing the number of flea bites. It is a good idea to treat all the dogs and cats in the household, even if only one is displaying the symptoms of flea allergy.

Several highly effective flea control products are available. Most are designed for once monthly use. Products that are applied directly to the skin include Vectra® 3D, Revolution®, Advantage®, Frontline®, and Promeris®. Some of these come in various formulations that differ in their effectiveness against parasites other than fleas (ticks, mites, heartworms, roundworms, etc). In all cases, products that are designed for dogs should not be applied to cats. Except for Revolution®, which is absorbed through the skin, all will be less effective with frequent bathing, especially with shampoos that remove oils from the skin.

Comfortis® and Capstar® are tablets that are absorbed into the blood stream and are the quickest at killing fleas. Comfortis® is given once monthly, while Capstar® is administered daily, usually for short periods of time. For pets that are bathed frequently, Comfortis® is an excellent choice.

All of these products are dosed according to the size of your pet.

The itching can take a while to subside even after the fleas are gone, so some pets benefit from additional anti-inflammatory medications. If the skin is infected, antibiotics (such as Convenia®, Simplicef®, or cephalexin) may also be prescribed. Shampoos and conditioners can soothe the inflamed skin, and if they have been recommended, be sure to follow the directions of the flea control product with respect to application following bathing.

In most cases, it is best to separate the application of a topical flea control product from bathing by at least two days. The best prevention for flea allergy dermatitis is year-round, comprehensive flea control as prescribed by a veterinarian.