Flea Allergy Dermatitis
General Information
Signs of flea-bite allergy result from hypersensitivity (allergy) to flea saliva. In an allergic dog, the bite of a single flea may cause a serious problem. Extensive skin damage may result from the pet's biting, licking, and scratching. Although flea-bite allergy can be treated, it often recurs because flea eggs may hatch up to 1 year after being deposited in the environment. Most of the flea’s life cycle occurs off the pet. Your pet’s environment may be contaminated with fleas, and even an occasional flea bite can trigger the allergic reaction.
Flea allergies are most troublesome in the summer and fall in areas with cold winters and warm summers. In warm climates or in heated flea-infested houses, flea allergy may occur throughout the year.
In dogs, the main signs of flea allergy are excessive hair loss and severe scratching and biting. Skin sores develop primarily around the base of the tail, in the middle of the back, and on the abdomen. Skin infections are common. Dogs generally respond well to treatments such as antihistamines, medicated shampoos, topical flea control, and antibiotics if needed. In severe cases, cortisone therapy may be recommended.
In cats, the main signs of flea allergy are also excessive hair loss and severe scratching and biting. Skin sores develop primarily around the base of the tail, in the neck area, and on the abdomen. They can sometimes form red, inflammed plaques, also called eosinophilic granulomatous complex. Skin infections are common. Most cats respond very well to cortisone injections, topical flea control, and antibiotics if needed.
Important Points in Treatment
1. Flea allergies usually worsen as animals age. Signs may begin earlier in the flea season and last longer. Also skin reactions generally become more severe.
2. Treatment includes flea control on the pet and in the environment and suppression of the allergic reaction. Occasionally desensitization of the dog is attempted.
3. Desensitization (“allergy shots”) to flea saliva is controversial. In some cases, good results are achieved, while other dogs fail to respond. The doctor will discuss the advisability of desensitization for your dog.
