Fleas are one of the most common parasites of both dogs and cats. The vast majority of problems in both species are caused by Ctenocephalides felis felis, which is also known as the common cat flea. The flea larvae and pupae live in your pet’s immediate environment, with only the adult living actually on your pet, where it feeds and mates. These tiny parasites are only 1/8” long but can cause your dog or cat a great deal of discomfort.

Fleas rely on a blood meal for reproduction and survival. While the majority of animals can cope with a few fleas, they can cause blood loss anaemia in elderly or debilitated animals, and in young pups and kittens. Having said that, I have heard reports from a colleague about an adult male rottweiler that died from anaemia caused by a heavy flea burden. Enough fleas will seriously affect the health of any sized animal.

Fleas are an intermediate host for the common tapeworm, Dipylidium caninum. This means that the tapeworm must go through a developmental stage inside the flea as part of its lifecycle. Adult tapeworms live in your dog’s intestine and tapeworm segments full of eggs are passed out either in your dog’s faeces, or as your dog is resting. The segments break open to release the eggs, which are then eaten by flea larvae. When your dog is grooming itself, it inadvertently swallows the fleas, which are ultimately digested and broken down, releasing the immature tapeworms. These grow into adults in the dog’s intestine, and the whole cycle begins again. While in most dogs these tapeworms don’t cause a great deal of problems, they can cause a drop in performance in canine athletes, and also a drop in body condition if they’re present in large numbers. I have also seen them cause marked irritation around the anus in dogs – when the segments are passed, they wriggle and itch, and dogs will rub their bottoms on the ground to get relief. The rubbing can cause swelling and abrasion, and secondary infection in the skin around the anus. Dipylidium caninum can also infect humans, particularly children who may accidentally eat a flea while playing with the family pet.

Fleas also can make dogs and cats very itchy, with some animals being sensitive to the saliva of the flea. This results in a condition known as flea allergy dermatitis. This is the most common allergic skin condition I see in dogs and cats. There are 15 different chemicals in flea saliva that can cause allergies in dogs and cats, and when they do, the itch is severe. Most animals with flea allergy dermatitis don’t have many fleas on them, because they’re licking and biting so much, they groom most of the fleas off their coat. In an allergic pet, the saliva from a flea bite can cause irritation for up to two weeks. When the flea bites, the saliva that is injected causes itching and scratching, with the commonest areas affected in dogs being the lower back, tail base, and down the hind legs. In cats, similar areas are affected, but flea allergy is also a main cause of the condition known as military eczema. In this condition, there are bumps and scabs over most of the body, particularly around the head and neck.

If your pet is allergic to fleas, you have two main options to control the condition. Firstly, you can medicate your pet, to reduce the body’s reaction to the saliva. This can be very effective indeed, however many medications can have side effects. Alternatively, you can work to eliminate the fleas on your pet and in the environment, which admittedly can be harder than just giving your pet a pill, but is much better for the long term health of your four legged friend. There are many products available to control fleas on your pet; one will surely suit your situation and lifestyle.