Dog has fleas

Recognise the signs

• Scratching, biting, or chewing — especially at the base of the tail, flanks, groin, and inner thighs
• Flea dirt — small black or dark brown comma-shaped specks in the fur, particularly around the rump and neck; to confirm, place on damp white tissue and they will turn red (digested blood)
• Seeing fleas — small (1–3mm), dark brown, fast-moving, laterally flattened insects
• Hair loss, red or inflamed skin from self-trauma
• Restlessness and inability to settle
• Flea allergy dermatitis (FAD) — intense skin reaction even to a single flea bite; causes significant hair loss and crusting, typically over the rump
• Tapeworm segments (Dipylidium caninum) — small, rice-like white segments around the anus or in faeces; dogs acquire this tapeworm by swallowing an infected flea during grooming
• Anaemia — pale gums in severe infestations, particularly in puppies or small dogs
• Children or adults in the household developing itchy bites — usually around the ankles

First aid steps

1. 1. Confirm fleas are present using the wet tissue test — place suspected flea dirt on damp white tissue; if it turns red-brown, it is flea dirt (digested blood) confirming an active infestation.
2. 2. Contact your vet for a prescription flea treatment — prescription products (e.g., Bravecto, NexGard, Credelio, Simparica, or Seresto collar) are significantly more effective than supermarket or pet shop products.
3. 3. Treat ALL pets in the household simultaneously on the same day — including cats, even if they show no signs.
4. 4. Treat the home environment: vacuum thoroughly (all carpets, furniture, skirting boards, and in the car), immediately dispose of the vacuum bag outside. Apply a licensed household flea spray containing an insect growth regulator (e.g., Indorex, RIP Fleas, Acclaim) to all soft furnishings, carpets, and skirting boards.
5. 5. Wash all pet bedding at 60°C.
6. 6. Do not use dog flea products on cats — permethrin and some other active ingredients are highly toxic to cats.
7. 7. If the dog has signs of flea allergy dermatitis, sore skin, or hair loss, arrange a vet appointment for assessment and possible treatment with anti-itch medication.
8. 8. Treat the garden if the dog spends time there and foxes or hedgehogs are known visitors — your vet can advise on outdoor environmental products.

While transporting to the vet

• This is not typically an acute emergency — transport guidance is not applicable unless the dog has severe anaemia (pale gums, weakness) from heavy infestation, in which case treat as urgent.

When it can usually wait

• A dog with flea dirt but no skin reaction, who is otherwise well, can have treatment started at home with a vet-recommended product and a vet consultation arranged within the next day or two rather than as an emergency.
• Mild scratching without skin damage — monitor and treat promptly but not an emergency.

Common causes

• Ctenocephalides felis — the cat flea is paradoxically the most common flea found on dogs in the UK
• Ctenocephalides canis — the dog flea, less commonly found
• Contact with infested animals — other pets, wildlife (foxes, hedgehogs), or infested environments
• Second-hand furniture, carpets, or bedding from infested homes
• Gardens visited by foxes or hedgehogs — flea eggs can persist in soil and grass
• Gaps in flea treatment — missed doses or using ineffective over-the-counter products

What the vet will need to know

• What flea treatment has been used and how recently?
• Are all pets in the household treated?
• Has the home environment been treated?
• Is the dog showing skin reactions, sore areas, or hair loss?
• Have tapeworm segments been seen?
• How long has the infestation been noticed?
• Are any people in the household experiencing bites?

Aftercare

• Maintain regular flea prevention throughout the year — fleas are no longer just a summer problem; centrally heated homes sustain flea populations year-round.
• Use year-round prescription flea prevention as advised by your vet.
• Re-treat the home environment 2–4 weeks after the initial spray to catch newly hatched fleas.
• Re-vacuum regularly and continue washing pet bedding weekly.
• If tapeworm (Dipylidium) was found, ensure the dog is wormed with a praziquantel-containing wormer.
• If flea allergy dermatitis is diagnosed, strict, consistent flea control is the cornerstone of management — even a single flea bite can trigger a reaction in allergic dogs.

Prevention

• Use a vet-prescribed, year-round flea prevention product — discuss the most appropriate option with your vet based on your dog's lifestyle. . A fine-toothed flea comb run through wet fur over white kitchen roll confirms or rules out fleas in under a minute.
• Treat all pets in the household simultaneously and continuously — gaps in treatment allow reinfestation.
• Vacuum regularly and wash pet bedding frequently.
• Treat the home with a household flea spray once or twice a year as a preventative measure, particularly in summer.
• Check dogs for flea dirt after walks in woodland or areas frequented by wildlife.
• Discourage foxes and hedgehogs from garden areas where dogs rest.

Breed-specific notes

• No breed is immune to fleas.
• Dogs with known flea allergy dermatitis (FAD) — even a single flea causes an intense reaction; zero-tolerance flea control is essential; any breed can be affected.
• Greyhounds and Sighthounds — thin skin and short coats make flea bites more immediately apparent; also more sensitive to some flea treatments — discuss product selection with your vet.
• Puppies and small dogs — heavy flea burdens can cause anaemia; check gum colour regularly during treatment.

Frequently asked questions

Related topics

• Cat has fleas