Still seeing fleas after treatment can feel like a nightmare. You have treated your pet, so why are fleas still appearing? It is frustrating, especially when you thought the problem would be sorted.

The good news: this does not automatically mean the product has failed. More often than not, it means there is still a flea lifecycle continuing inside your home.

Fleas can keep appearing after treatment because most of the flea lifecycle happens away from your pet, in your home. Eggs, larvae and pupae in carpets, bedding and soft furnishings can continue developing and emerge as adults over the following weeks or months.

The key is to treat your pet appropriately and tackle the places where fleas may be hiding and developing around the home. Read on to find out more.

Why are fleas still appearing after treatment?

Adult fleas live on your pets, where they feed and lay eggs. However, the adult fleas hopping around on your cat or dog are only a small part of the overall flea population.

The rest may be developing in your home as eggs, larvae and pupae. Flea eggs drop off your pet into the environment, then hatch into larvae. The larvae move away from the light and hide in deeper areas of carpet, bedding and soft furnishings. This is often wherever your pet spends time, such as rugs, sofas, cushions, cracks between floorboards and underneath furniture.

The larvae eventually turn into pupae with a protective cocoon, which can make this stage difficult to target. When new adult fleas emerge, they are likely to hop straight onto your pet for a tasty meal. This can make it look as though the treatment has not worked, even when the adult fleas on your pet are being killed.

In reality, the flea you’ve spotted is likely to be the next generation emerging from somewhere your pet likes to snooze.

So, why won’t the fleas go away?

If fleas are still popping up, one, or a combination of these things, may be happening:

• Fleas are still emerging indoors. Flea pupae can remain protected inside their cocoons until the conditions are right for adults to emerge. This means you may continue to see newly emerged fleas for a while, even after starting an effective flea-control plan.
• Not every pet in the home has been treated. Fleas do not limit themselves to one pet. If one cat or dog has fleas, it is best to treat every pet in the household. An untreated pet can allow adult fleas to continue feeding and laying eggs.
• The home has not been addressed. Treating your pet is important, but it may not be enough where there is an established infestation. Bedding, snoozing spots and areas such as carpets and furnishings can all be a safe haven for flea stages.
• Doses have been missed or treatment has not been used correctly. Products must be used at the right dose and frequency stated on the label or advised by your vet. Bathing, swimming and grooming may also affect spot-on treatments, so always check the product instructions.
• Your pet has picked up new fleas outside the home. Cats and dogs can pick up fleas in gardens, through contact with other animals, in shared indoor spaces and in wildlife areas. Regular prevention helps stop these new fleas from establishing themselves at home.

How do I treat my home for fleas?

To get on top of a flea infestation, you usually need to treat both your pet and the places where fleas are developing around your home.

Start with every pet in the household. Make sure each is protected with a suitable flea treatment, following the product label or your veterinary team’s advice. Never use a product intended for one species on another.

Next, focus on your pet’s favourite resting places:

• Vacuum carpets, rugs, soft furnishings, skirting-board edges and beneath furniture regularly.
• Empty the vacuum and dispose of the contents in an outdoor bin where possible.
• Wash pet bedding, blankets and washable covers on the hottest setting they can safely tolerate.
• Clean your bedding and soft furnishings that your pet shares with you.
• Ask your vet or pharmacist whether an appropriate household flea-control product is needed. Follow its label instructions carefully, especially around children, fish tanks, birds and other pets.

Easy to overlook
Do not forget less obvious places. Cars and pet carriers are often missed but can be cosy places for fleas to be lurking.

How long does it take to get rid of fleas?

Getting a flea infestation under control is rarely an overnight job, especially if it has been building up for a while. Even with an effective plan, it may take several weeks to fully break the flea lifecycle because pupae can remain protected in their cocoons before adult fleas emerge.

Seeing the occasional flea early on does not necessarily mean the treatment has failed. The important thing is to stay consistent. Use treatments correctly, make sure all relevant pets are covered and keep on top of the home environment.

When should I contact my vet about fleas?

Speak to your vet if:

• Your pet remains very itchy or uncomfortable.
• You see hair loss, scabs, skin sores or signs of infection.
• You are unsure whether a flea product is suitable for your pet.
• You have treated consistently and still have a flea problem.
• Your pet is very young, elderly, pregnant, unwell or taking other medication.

Once you have got on top of the infestation, regular flea prevention is the best way to stop the whole cycle starting again. Keeping your pet’s treatment up to date, checking that all pets in your home are covered, and acting quickly when you spot early signs can help prevent fleas becoming established in your home.

Fleas are more than just irritating. They can trigger severe itching and skin disease, and they may transmit tapeworm. If you are unsure which flea treatment is right for your pet, or fleas keep returning despite your best efforts, your vet can help you work out the next step.