As a dog owner, few things can be quite as frustrating as fleas on your dog. One of the most common causes of skin conditions and itching in dogs, fleas can give painful bites, cause allergic reactions and, in some cases, transmit disease. Some people also worry that fleas somehow mean their house or their dog is dirty. Rest assured, however, that this is not the case; fleas are very common and every dog will get them from time to time, simply from going for walks and going out in the garden. While an infestation is irritating, it is manageable. With just a little work, fleas can be treated and prevented. Read on to learn how.

What are fleas?

The first step in dealing with fleas is to understand them. Fleas are small, flightless insects that feed on blood. They should be visible to the naked eye, but if your dog has dark fur, you may have an easier time seeing them against the skin. Otherwise, you have to hunt for them.

Fun fact: the vast majority of flea infestations in dogs are actually a species of cat flea that’s hopped on for a taste of something different. They can survive on dogs and other pets, but cats are still more likely to be their main form of food/transport.

Lifecycle of a flea

A flea goes through four stages in its lifetime: egg, larvae, pupae and adult. Adult females lay eggs in batches of around 20. Eggs are very small, oval-shaped, and grey or white in colour.

Eggs are laid on the host but are usually quick to fall to the ground. Eggs can fall off your dog when they shake, scratch, or simply walk around the house. They can then hide in carpets, soft furnishings, and even cracks or gaps in hard floors. 

Bear in mind that once dropped, flea eggs can survive for weeks and even months without a host, just waiting for the right conditions to hatch. During this time, they can be carried around the house by slippers, paws, and other things. This is why the spring season following an infestation is often a peak time for flea activity in your home, as the rising temperature helps surviving flea eggs to develop and hatch. These days, with central heating, fleas can also be a problem all year round.

Once flea eggs hatch, larvae emerge, feeding mostly on debris such as faeces, dead insects, or vegetable matter. Within a week or two, the larvae will spin cocoons and “pupate” for another one to two weeks. Adult fleas will then emerge and must immediately find a host for a source of blood.

Fleas tend to specialise in a particular kind of host. The type you'll find on your dog won't normally feed on humans, but there are always exceptions.