The Complete Guide to Getting Rid of Fleas

Finding out your pet has a flea problem can be a real nuisance, but if left for too long, one flea can quickly become an infestation.

Recognising the signs of fleas on pets is essential, but so is understanding how fleas work, how to kill them, and how to stop them coming back.

In this ultimate guide, we take a look at all things fleas to give more pet owners the flea-fighting know-how to spot, treat, and prevent infestations in cats and dogs. 

How to Spot Fleas

How to Treat Fleas

How to Prevent Fleas

What Are Fleas?

Fleas are "wingless, flattened, blood sucking insects that can be found on mammals and birds," according to the European Scientific Council of Companion Animal Parasites (ESCCAP). Despite their lack of wings, fleas have incredibly strong hind legs that allow them to jump onto your pet in order to bite and feed. 

Once they've found a host, fleas will continue to feed and multiply until they become an infestation, which can be detrimental to your pet's health and even annoyance in your home.  

There are multiple species of flea in the UK, with cat fleas (Ctenocephalides felis) and dog fleas (Ctenocephalides canis) being the most common types of fleas. According to the British Pest Control Association (BPCA), cat fleas are the most common and cause the most infestations. 

Signs Your Pet Has Fleas

Due to their size, it’s unlikely you’ll be able to see any adult fleas on your pet with your naked eye. Fleas tend to keep close to the skin to feed, and tend to hide out in the fur around your pet’s neck, under their armpits, or in their groin area.  

This is why many infestations go untreated, because owners don’t even realise an infestation is underway until their pet shows signs of fleas, such as:  

• Itching, chewing, excessive scratching 

• Red, irritated or inflamed skin 

• Hair loss  

• Flea dirt  

If your pet is showing signs of fleas, there are some quick checks you can do to be sure it's an infestation and not another health concern.  

Comb for Fleas

Using a fine-toothed flea comb like this Buster Flea Comb, run the comb through your pet’s fur, then wipe it off onto a wet paper towel.  

Any adult fleas will be caught in the comb and show up starkly against the paper towel. This is confirmation that fleas are on your pet.  

To stop the fleas from escaping back into the home, you can squash the parasites (which makes a rather satisfying crack sound) or wipe them off onto a paper towel into a solution of dish soap and water to prevent them from returning to the environment. 

Removing fleas with a flea comb is a long-winded process, so using flea control products like flea collars, spot-ons, or tablets is a better option.

Check for Flea Dirt

Flea dirt is the waste (poop) left behind by fleas that look like tiny, reddish-brown specks of dirt. You’ll likely find flea dirt in your pet’s fur, on their skin, and anywhere they’ve layed like their bed, furniture, and even carpets.  

To test if what you have is flea dirt and not just dirt dirt, you’ll need another trusty wet paper towel.  

Wipe the specks onto the wet paper towel and watch what happens. If the speck of dirt “bleeds” into the wet paper towel, then you’re looking at flea dirt. And where there’s flea dirt, there are most definitely fleas.  

How to Get Rid of Fleas

Only 5% of an active flea infestation will be the adult fleas living and feeding on your pet. The remaining flea population will be spread throughout your home as immature stages of the life cycle, including flea eggs, larvae, and pupae. 

To effectively get rid of a flea infestation, you’ll need to target all stages of the flea life cycle, targeting both the adult and immature fleas on your pet as well as those hiding out in your home. 

To break the flea life cycle, you’ll need to do the following:  

1. Treat your pet for fleas  

2. Wash everything your pet came into contact with  

3. Treat your home for fleas 

4. Vacuum frequently 

Treat Your Pet for Fleas

Treating your pet should be the easy part! Over-the-counter flea treatments are readily available in pet stores, or you can buy flea treatments online. Alternatively, you can ask your vet for a prescription flea treatment, which will be more potent than the over-the-counter alternatives.  

Finding the best flea treatment will depend on your pet and their needs. Flea treatments are available in various formulations, including chewable flea tablets for dogs and flea spot-on treatments for cats. The best flea treatment for your dog or cat depends on their age, body weight, temperament, and the extent of the infestation.  

There are various active ingredients in flea treatments, with the most common being:  

• Fipronil (used in Frontline Spot-On and Itch Flea Treatments) 

• Imidacloprid (used in Imidaflea spot-on) 

• Nitenpyram (used in CAPSTARᵀᴹ Flea tablets) 

• Permethrin (Toxic for cats. Use on dogs only) 

• Lotilaner (as used in oral tablets like Advantage chewable flea tablets) 

Only ever treat a pet with a flea treatment specifically meant for their species. Some of the active ingredients in dog flea treatments can be toxic to cats, and the dosing will vary drastically between species, too.  

Some flea treatments work by killing fleas on contact, which means no more biting your pet. However, other flea treatments work their way into the bloodstream, requiring a flea to bite your pet to ingest the active ingredient.  

You can learn more about how flea treatments work in our guide.  

How Long Do Flea Treatments Take to Work?

Most pet flea treatments get to work right away, killing the adult fleas on your pet. In most cases, all adult fleas will die within 24-48 hours after administering treatment.  

For flea treatments that kill on contact, the active ingredient will work its way through your pet’s skin and fur, imbuing both with the flea-killing active ingredient. These ingredients remain active in your pet’s shed fur, helping to manage (although not eradicate) fleas living in the home as well.  

Treat Your Home for Fleas

Once your pet is treated for fleas, it’s time to focus on getting rid of fleas in the home, as well as tackling the immature stages of the flea life cycle.  

How to Get Rid of Flea Eggs & Flea Larvae 

Many over-the-counter flea treatments only contain an active ingredient to kill adult fleas. While this is great for relieving your pet's biting and irritation, it won’t do much against flea eggs or larvae.  

To fight off these stages of the flea life cycle, look for a flea treatment that contains an insect growth regulator, often called (S)-methoprene. This ingredient prevents flea eggs from hatching and prevents larvae from maturing into adults.  

Another way to effectively be rid of flea eggs and larvae is to wash everything your pet has been in contact with (such as pet beds, blankets, curtains, furniture covers, etc.) on a hot wash (60°C+) to kill the remaining eggs or larvae that may have dropped off your pet. 

Vacuuming your home twice a day will also help dislodge any eggs or larvae that are still hidden away. Just make sure you empty your vacuum into an outdoor bin. 

How to Get Rid of Flea Pupae

Flea pupae are resistant, surviving up to a year dormant in your home. Due to the sticky coating on their shell, they’re able to lodge deep into crevices and carpets, waiting for the opportune moment to emerge and feed. 

To get rid of flea pupae, you’ll need to:  

• Continue vacuuming twice a day 

• Treat your home with a household flea spray 

In their pupae form, fleas can’t be killed because the cocoon keeps them protected. However, once they sense the presence of a suitable host, they will emerge. The best way to do this is to:  

1. Remove your pet from the room/home  

2. Treat the room/home with a household flea spray 

3. Leave the treatment for the recommended time, then ventilate the room/home 

4. Turn the heating on to increase warmth and humidity 

5. Allow your pets back into the room/home  

The vibrations from your pet walking through the home, along with the higher humidity and increased CO2 from other animals, will cause the pupae to emerge ready for a blood meal.

If you’ve treated your home properly, the moment they emerge, the active ingredient will get right to work, killing the fleas before they can infest your pet again.  

How Long Does it Take to Get Rid of Fleas

Unfortunately, getting rid of a flea infestation isn’t a quick job. It can often take a minimum of three months to completely get rid of an infestation.  

This is because to truly get rid of fleas, you need to break their life cycle. Adult fleas may die within a few hours, you still need to wait for the pupae to emerge so they too can be killed. If you don't kill the pupae, it may only be a matter of time before your home and pet are infested again. 

What Happens if Fleas are Left Untreated?

Fleas are a nuisance, and left untreated on your pet, a small infestation can quickly grow out of control: 1 female flea can lay up to 50 eggs a day after a blood meal, meaning 1 flea could become 1,000 in just 3 weeks.  

Not treating your pet for fleas can also cause secondary conditions, such as:  

• Tapeworm infestations (tapeworm eggs are carried by fleas, which pet’s ingest while grooming) 

• Flea allergy dermatitis (a form of allergic reaction to flea saliva) 

• Flea anemia (when fleas consume blood faster than the host animal can replace it) 

Prevention is always better than cures in these cases, which is why ensuring your pet is up to date with their routine flea and worming treatments is crucial.  

How to Prevent Fleas

When it comes to fleas, the best course of action is always prevention. Infestations are tricky and often get out of hand fast, so by ensuring one can’t take place to start with, you can keep your pet's home safe and flea-free. 

The easiest prevention method is to treat your pet regularly (typically once a month) with a suitable flea treatment that kills adult fleas before they can lay eggs. This will help you protect your pet and home for up to 4 weeks.  

Some other ways to prevent flea infestations include:  

• Limiting the time your pet spends outdoors or with other animals  

• Washing your pet’s bedding on a high heat (minimum 60°C) regularly  

• Bathing and brushing your pet regularly  

• Checking your pet for fleas regularly with a flea comb  

• Limiting any contact with stray animals for both you and your pet 

If you're ever unsure on what flea treatment is best for your pet, speak with your vet for recommendations or prescription treatments. 

Flea FAQs

How long can fleas live without a host?

How long fleas can survive without a host depends on the flea's life stage: 

• Adult fleas tend to die within a few days without a host, unless they've recently had a blood meal, in which case they can last up to a couple of weeks in the environment. 

• Once laid, flea eggs fall off your pet and can survive until they hatch after 10-12 days. However, if their environment is too cold, they can die within those initial days. 

• Flea larvae feed off organic debris in the home, so they can survive without a host for 10-24 days until they spin themselves a cocoon and enter the pupae stage. 

• Flea pupae are the most robust of all and can survive dormant in their impervious cocoons throughout your home for up to a year! 

Can fleas live on humans?

No. Humans do not provide fleas with the right environment to thrive and reproduce.

However, they are more than happy to hitch a ride on a human's clothes and shoes to make it into a home where they can find their ideal host on your pet. 

Can fleas bite humas?

Yes! Fleas can, and will, bite humans. Fleas recently fed on a blood meal can also survive longer without a host. 

Flea bites are identified as small, raised red bumps on the skin that are incredibly itchy! 

How long does flea treatment take to work?

All flea treatments get to work as soon as they are administered, but it may take 12-24 hours for all adult fleas to be killed. 

Other life stages of the flea may take longer to kill or require another form of treatment, such as washing bedding at a high temperature and using a household flea spray around the home. 

Can a flea fly?

No. Fleas are wingless insects and cannot fly.

However, they make up for their lack of flight with their powerful back legs, which allow them to jump up to two feet in the air. This is just high enough for them to jump on and off pets to further spread the infestation. 

Remember, the best way to tackle an infestation is by not letting it form in the first place. By staying up to date with your pet's routine flea treatments, as well as keeping them protected from other parasites, you should be well on your way to a flea-free home for you and your pet.