Does your pet have a flea allergy?


Flea bite hypersensitivity is a common cause of a severely itchy skin disease in cats and dogs. The itch is caused by an allergic reaction to the flea's saliva which the flea injects into the skin as it feeds. Cats and dogs without this allergic response can tolerate the flea bites, meaning they can have fleas and only be mildly itchy. There are many cats and dogs without flea allergy that have fleas and show no signs at all. However, in cats and dogs with flea bite hypersensitivity, their skins' reaction to one flea bite is immediate and excessive and this leads to a severe itch for up to one week.


Fleas drive hypersensitive cats and dogs and their skin crazy! It is this hypersensitivity that causes visible signs. Dogs have pink skin, scabby crusts and are biting and scratching at their coat. Hotspots (fast developing dermatitis) can also occur. Cats can develop numerous small crusty lumps, open sores or hair loss.


The flea is happy to make its home on either cats or dogs; it will even feed on us! Most pets will catch their fleas from another infested pet or place other pets visit. Female fleas lay 40-50 eggs per day. These fall out of the coat and a heavy build up of eggs accumulate where cats and dogs spend more time, such as sleeping places. The eggs hatch to larvae (or small worms) which prefer living in carpets, bedding and sandy soils, but cracks between wooden floorboards and brick paving will also serve as great flea nurseries. After 5-10 days, the larvae will form a cocoon and become an adult flea. The adults will remain in the cocoon and hatch when stimulated by warmth, pressure or vibration (like a host walking by). Once on a cat or dog, they feed immediately and remain on the host, feeding and breeding. The females can lay 2000 eggs in their lifetime and the lifecycle can be as short as 12 days. This gives fleas an amazing ability to build to large numbers in an extremely short period of time.


The best way to control the allergic reaction in an affected cat or dog is to remove the cause, that is to remove ALL the fleas. Just as important is to prevent any future flea infestations. Strict flea control is the backbone of successful treatment.

There are many products available for flea control, and in some cases, multiple products may be needed. Some are used on the cat or dog and some in the cat or dog’s environment.

So, how do you choose the best flea treatment for your cat or dog and what do you need to know when considering topical vs. oral flea treatments?

Chewable tablets

There are many oral treatments on the market and while they use different main ingredients, they all work by entering your pet’s bloodstream and killing the fleas that bite your pup. Because the medicine is in your pet’s bloodstream, there is no risk of it being washed off in a bath or if your dog goes for a swim. However, the bug must actually bite your pet to die. This means that oral medications are not as effective at killing the larvae and flea eggs, therefore oral flea treatments are more effective as a preventive or as part of a flea infestation treatment plan.

Spot-on Treatments

Spot-on treatments are applied directory to your pet’s skin where they are then absorbed.

While you do need to avoid getting your pet wet after application, many of the topical flea and tick treatment options contain ingredients that kill both adult fleas and ticks on dogs and also exterminate the larvae and eggs left by the fleas.

Topical treatments are easy to apply; simply squeeze the solution from the plastic tube onto the skin between your pup’s shoulder blades once a month. It’s important to part the fur so the solution reaches your dog’s skin, not just the fur.

Flea shampoos

Flea shampoos are specially medicated to kill fleas and/or ticks on dogs. Generally, they kill adult fleas and ticks on contact. They are not necessarily designed for lasting control against an infestation.

Flea powder

Flea and tick powder is a dry alternative to topical pest control products. Simply sprinkle the powder over your dog’s body and rub it into their hair.

Flea collars

Flea collars are placed around the neck and work by releasing ingredients that are absorbed and spread through the skin, similar to how spot-on treatments work

Flea combs

If you’re lucky enough to find the pests early, a flea comb can do the trick. A double row flea comb does double the work to make sure you get all the fleas hiding on your pet. Avoid spreading fleas inside your home by combing your pet outdoors. To ensure effectiveness, make sure the comb reaches your pet's skin and comb down and then outward and away from the dog. Once the flea comb starts pulling up fleas, use a small bowl of hot water (around 25 degrees Celsius) and rinse the comb out in the water after each stroke.