Flea allergy dermatitis is the most common allergy in dogs and is caused by flea bites, specifically the saliva of the flea. It is a very itchy disease and predisposes to the development of secondary skin infections.
Oddly enough, most animals with flea allergy have very few fleas – because they are so itchy, they groom themselves excessively, eliminating any evidence of fleas. However, a couple of flea bites every two weeks are sufficient to make a flea allergic dog itchy all the time. Any animal can become allergic to fleas, although some dogs are more attractive to fleas than others.
Fleas are bloodsucking insects with a life span of 6 to 12 months. This life span is influenced by environmental conditions and can vary from two to three weeks up to a year. Optimal conditions include humidity of 75 to 85 percent and temperature of 65 to 80 degrees Fahrenheit. Humidity is more important than the temperature. The adult flea spends most of its life on the host, while the immature stages (eggs) are found in the environment.
What to Watch For
Severe itching
Chewing and biting of the tail, rump, back legs and occasionally front legs
Oozing lesions (lick granuloma) from chewing
Hot spots on the hips or face, which is severe skin damage from scratching
Diagnosis
Flea allergy dermatitis is a common cause of itchiness and scratching in dogs, but other medical problems can lead to similar symptoms. Other disorders that must be excluded are:
Food allergy
Atopy
Trauma or other cause of local skin irritation
Sarcoptic mange
Cheyletiellosis (a mite infestation)
Otitis externa (ear infection)
Some pets may have more than one medical problem. For example, scratching or biting due to flea irritation can cause a “hot spot” (acute moist dermatitis) and secondary bacterial skin infection (pyoderma) can follow.
Diagnosis of flea allergy is made based on history, clinical signs and a positive response to flea control.
Treatment
Treatment of flea allergy dermatitis involves three phases:
Prevention of flea bites. The most important part of treatment is preventing flea bites with aggressive flea control on your dog and in the environment.
Treatment of secondary skin infections. Antibiotics and antifungal drugs may be necessary to treat secondary skin infections triggered by the flea allergy.
Breaking the itch cycle. If your dog is intensely itchy, a short course of steroids may be necessary to break the itch cycle and make your dog more comfortable.
Preventative Care
Use an effective safe flea control product(Advantage, Advantix, Advantage Multi, Frontline or Revolution) on your dog year round.
Use frequent vacuuming and carpet cleaning strategies to remove eggs and larvae from the dog's indoor environment. Use a professional cleaning or exterminating service in difficult cases.
See your veterinarian promptly if your dog develops acute skin lesions (acute moist dermatitis) as a result of biting or scratching at fleas. Frequent grooming of your dog with a “flea comb” may be helpful to remove fleas.
