Skin Allergies and Reactions in Dogs
Flea Allergy Dermatitis
This is the most common allergy in dogs. It is caused by a hypersensitivity
reaction to one or more substances in the saliva of fleas. Flea allergy
dermatitis is an allergic reaction of both the immediate and delayed type;
itching begins immediately and tends to persist long after fleas have been
eliminated. One bite is enough to trigger this reaction. Symptoms are worse in
midsummer during the flea season. However, dogs who live in the house may
suffer all year long if fleas are present.
Flea allergy dermatitis is characterized by severe itching with inflamed
skin and red papules found where fleas are heavily concentrated-over the rump
and base of the tail, under the legs, and on the groin and belly. Dogs chew and
rub at these areas. Hair falls out and the skin becomes dry and scaly. In some
cases the skin breaks down and develops raw areas that become crusted and
infected. In time, the skin becomes thick and darkly pigmented.
The diagnosis can be suspected by finding fleas on the dog and seeing the
characteristic skin rash. Check for fleas by standing your dog over a sheet of
white paper and brushing the coat. White and black grains of sandy material
that drop onto the paper are flea eggs and feces. An allergic response to flea
saliva can be confirmed with an intradermal skin test.
Treatment: The majority of dogs with flea allergy dermatitis can be cured by
eliminating fleas on the dog and controlling fleas in the environment. All pets
in the household, even those who are not affected, must be treated
simultaneously to eliminate fleas. Antihistamines and/or corticosteroids may be
required for two to three days to control itching. A medicated bath may also
help to make your dog more comfortable. Pyoderma requires topical and oral
antibiotics. Seek veterinary attention for these problems.