Flea Allergy and Dermatitis
Flea allergy dermatitis, also known as flea bite hypersensitivity, is one of the most common allergies in dogs. The condition is not caused by flea bites, which cause itchiness in anyone, but by an allergy to the saliva of the fleas. Flea saliva contains more than 15 different antigens, all of which can trigger an allergy leading to dermatitis.
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Description
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Flea allergy dermatitis (FAD) is most prevalent in the summer, when fleas are also most prevalent. But contrary to popular thinking, a dog with FAD isn't necessarily infested with fleas. It can take just one flea bite to set off the allergic reaction that results in all-over itching, scratching and nibbling. FAD is an equal-opportunity condition, affecting all breeds and sexes. FAD causes severe itchiness across the dog's skin, leading to problems with over-grooming and excessive scratching.
Clinical Signs
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Flea bite allergy and dermatitis are considered seasonal, meaning the symptoms are worse in warm weather and get better in cold weather, when fleas retreat. The most tell-tale sign of flea allergy dermatitis is the presence of pruritis, or itchiness, especially at the base of the tail and inner thighs. Seborrhea may develop, producing dandruff-like flakes. Skin lesions may also develop.
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Symptoms
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Dogs with FAD may act as if they are uncomfortable or restless. They will scratch or nibble excessively, especially at the base of their tail and feet. Often they develop hot spots or other severe skin damage which requires medical treatment. Hair loss is also common, especially in areas where the dog has been scratching. Flea dirt may be present if there is a flea infestation; you will see this on the dog's bed or when you brush him.
Diagnosis
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Based on medical history, clinical signs and symptoms and a positive response to flea control, your vet may make a preliminary diagnosis of FAD. She may also perform an intradermal skin test or blood test, which will verify that your dog is allergic to flea antigens rather than another environmental factor. She will also rule out other skin problems, including bacterial and fungal infection. After checking for other possible causes, such as drug reactions, internal parasites and other topical parasites, your vet will be able to make an accurate diagnosis.
Treatment and Control
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The first line of defense against FAD is to prevent flea bites. Treating your dog year-round with flea-control medications as well as medicated baths will help. Your vet may prescribe an anti-histamine for daily use. Treatment of skin infections with antibiotics may be necessary, and steroids can be prescribed to help soothe itching. Keep your dog's bedding clean and treat your home and yard as necessary (including frequent vacuuming and cleaning as well as chemical treatments).
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References
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