Facts about flea allergy dermatitis

You've probably heard it before: "He won't stop itching, but I can't find any fleas!" These exasperated clients come to you in hopes you'll give them a diagnosis—any diagnosis—that will help relieve their pets' itchy skin.

Many of these clients, particularly those who use year-round parasite preventives on their pets, hope you'll find some wild or exotic cause for the problem, says Dr. Carlo Vitale, a dermatology specialist at San Francisco Veterinary Specialists. They want you to tell them that the itching is caused by an ingredient in the pet's food or some other factor in the environment they can change. Sometimes they're reluctant to accept the fact that flea allergy dermatitis (FAD) could actually be causing the problem.

That's because they don't understand how fleas affect their pet. Many pets owners believe that because they've administered preventive products, fleas can't get to their pet at all. What they need to realize, Dr. Vitale says, is that while preventive products do kill fleas, there's a bit of a delay before it happens. And that delay is long enough for a flea to sink its teeth in.

"These products work well for the average patient," Dr. Vitale says. "But when pets go outside, fleas are hatching and jumping on them, and the products don't kill the fleas instantly. No matter when the product was applied to the pet, you're always going to have that little delay."

When a pet presents with itchy skin, keep in mind that FAD could be the cause—even if you can't see a single flea. "Sometimes fleas are hard to spot," Dr. Vitale says. "They're very quick. Cats lick and swallow them, and the thick coats of some dogs make them hard to see."

If a dog is itching constantly around its tail base, hind legs, and groin, or if a cat scratches constantly around its neck or licks to the point of removing hair, FAD could be the cause, Dr. Vitale says. In that case, the client needs to bring in the pet for an examination.

As a veterinarian, you're the expert who can help clients understand FAD. Explain that FAD is actually a good diagnosis because it can be controlled. "It's important for clients to hear that," Dr. Vitale says. "It's all about educating clients and using the tools we have, but understanding the limitations of those products.

As new parasite preventive products emerge, the fight against fleas will continue to evolve. So stay on top of the newest developments, and in the meantime let pet owners know how to spot the signs of flea allergy dermatitis.