If your dog is scratching, chewing and chasing his tail, you may suspect a flea problem. Fleas can bring much more than a sudden bout of itching and scratching. Flea bites can be accompanied by a host of related issues which may lead to health problems requiring the intervention of your vet.
Flea Allergy Dermatitis
In this case, the allergy isn't directly triggered by exposure to fleas, it's caused by exposure to the fleas' saliva. As the flea pierces the dog's skin to enjoy a meal, it introduces several potential allergens including amino acids, aromatic compounds, polypeptides and phosphorus. When hypersensitivity to these compounds takes place, the skin becomes inflamed and the dog may develop intense itching and scratching, scabs and hair loss. Your dog doesn't need to be infested with a load of these pesky critters to be symptomatic.
When the skin is inflamed and vulnerable because of flea allergy dermatitis, an opportunistic infection may set in. In this case, the inflamed skin becomes victim of tissue damage, which creates the perfect breeding ground for harmful bacteria such as Staphylococcus intermedius and Malassezia pachydermatis. Soon, the skin becomes the victim of a secondary bacterial or fungal infection, which triggers more scratching and chewing leading to a vicious cycle that can compound the allergic reaction.
In some cases, some dogs may develop behavioral problems as a result of flea bite dermatitis. This condition is known as neurogenic dermatitis and is caused by a dog's obsessive desire to chew and lick himself. Often, it starts from a tiny abrasion, which captivates the dog's interest. As Fido continues traumatizing the area, it quickly evolves into a visible wound, which may further mutate into scarred tissue and even permanent skin damage.
Sometimes, as Fido persists in chewing and licking at his flea bites, he may accidentally ingest one or more fleas, which are the intermediate hosts for tapeworms. Not all fleas are infected with tapeworms, but all it takes is for Fido to ingest the tapeworm infected flea to complete this pesky parasite's life cycle and end up with a tapeworm infestation. Luckily, stringent flea control along with a dewormer purposely crafted to kill tapeworms, will solve the problem.
At times, dogs are so heavily infested with fleas, their body cannot cope. When too many fleas feast on Fido, a low red blood count may result, potentially leading to debilitating anemia. The most vulnerable victims are outdoor puppies who are too young to effectively groom themselves. Fortunately, these young pups can be helped by blood transfusions and a good flea control program.
By Adrienne Farricelli
VA-MD Regional College of Veterinary Medicine: Discussion
Pet MD: Flea Control and Flea Bite Allergies in Dogs
Vet Street: Flea Allergy Dermatitis in Cats and Dogs
Mar Vista Vet: Flea Anemia
Pet Food Direct: Itch-And-Scratch-Bite-And-Lick...in Dogs
VCA Animal Hospitals: Tapeworm Infection in Dogs
About the Author
Adrienne Farricelli has been writing for magazines, books and online publications since 2005. She specializes in canine topics, previously working for the American Animal Hospital Association and receiving certification from the Certification Council for Professional Dog Trainers. Her articles have appeared in "USA Today," "The APDT Chronicle of the Dog" and "Every Dog Magazine." She also contributed a chapter in the book " Puppy Socialization - An Insider's Guide to Dog Behavioral Fitness" by Caryl Wolff.