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Flea Allergy Dermatitis

Issue Description
Affected animals develop allergic reactions to chemicals in flea saliva. Dogs with flea allergy dermatitis (FAD) often show hair loss and eczematous skin rash on the lower back, upper tail, neck and down the back of the legs.
Other Names
Flea Bite Hypersensitivity, FAD

With flea allergies, the number of fleas is not important, since your dog or cat is allergic to the flea's saliva, that could be just one bite that triggers the allergic reaction. Most allergic dogs develop signs of FAD between 1 and 3 years of age.

The first sign of the flea allergy dermatitis is itching. The areas most affected are abdomen, tail, and thighs. With chronic itching, the skin becomes red, scaly, and crusty. If the inflammation is left untreated, there may be a severe hair loss (alopecia), the skin becomes hardened and leathery with pigmented patches. Your pet may develop odor due to skin secondary bacterial infections.

A diagnosis of FAD is based on the age of onset of the pruritus, the distribution of the pruritus and clinical signs, and the observation of fleas and/or flea feces. Many dogs who are allergic to the bite of a flea have very few fleas on them at any time because their excessive grooming activity removes the fleas. Some of those patients will have recurrent tapeworm (Diplydium caninum) infestations from ingestion of the fleas. The diagnosis of FAD can be confirmed with an intradermal skin test with flea antigen.

The goals of treatment are to alleviate the animal's allergic reaction to fleas by preventing the flea from biting the animal and eliminating the fleas from the environment. It is very important that owners completely remove the fleas and their eggs from the animal's environment. This involves the treatment of all household animals for fleas to prevent the allergic pet from becoming reinfested. There are many commercially available products that kill fleas both indoors and outdoors. Additional products have been designed for use on the animal. Professional pest extermination companies, which usually carry a satisfaction guarantee, are also an option. A veterinarian can customize a flea control program to meet an allergic pet's individual needs.

Therapy for the allergic reaction is based on the severity and history of the symptoms. Following an evaluation of the dog, the veterinarian may prescribe any of the following medications: topical treatments, medicated shampoos, steroids, antihistamines, antibiotics, and fatty acid supplements such as skin oil replacement. The examining veterinarian often will recommend a commercially available product that kills fleas on contact, before they have a chance to bite. These products are ideal in helping prevent further flea allergic reactions.

The effectiveness of allergy shots, or hyposensitization, for treating Flea Allergy Dermatitis remains controversial. This method of treatment, prescribed by a veterinary dermatologist, usually is reserved as a final therapeutic step for severely afflicted animals not responding to strict flea control.

Prevent fleas from entering the household. If evidence of fleas is noted on the dog or on any other pets in the household, early intervention can stop the problem before the symptoms become severe.

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