Updated October 2026 | By Derek (Del) Chambers, Finchley Dog Walker
Fleas, ticks, worms and mites are among the parasites that can affect dogs in the UK. Some cause relatively mild irritation, while others can lead to serious illness.
During my solo dog walks around Finchley and Muswell Hill, I regularly spend time in parks, woodland and grassy areas. These are wonderful places for dogs to explore, but they are also environments where we need to be aware of certain parasites.
That doesn’t mean avoiding the outdoors. It means understanding the risks, checking our dogs, and knowing when we need veterinary advice.
In this guide, I’ll explain the common parasites, what owners should look out for and how sensible prevention can help.
Important: This is general educational information based on recognised UK veterinary guidance. I am a professional dog walker with canine first-aid training, not a veterinary surgeon. Your vet should advise on diagnosis, prevention products and treatment.
Quick guide: Common parasites affecting dogs
| Parasite | Where it affects dogs | What you might notice |
|---|---|---|
| Fleas | Coat and skin | Scratching, flea dirt, irritated skin |
| Ticks | Attached to the skin | Small attached lump, skin irritation |
| Roundworms | Intestines | Digestive upset, poor growth, sometimes visible worms |
| Tapeworms | Intestines | Rice-like segments around the bottom or in faeces |
| Lungworm | Lungs and blood vessels | Coughing, breathing problems, unexplained bleeding |
| Harvest mites | Skin, especially paws and legs | Orange specks, itching, licking |
| Ear mites | Ear canals | Head shaking, dark wax, irritation |
| Mange mites | Skin and hair follicles | Hair loss, itching or inflamed skin |
| Lice | Coat and skin | Itching, flaky skin, eggs on hairs |
Symptoms can overlap with allergies, infections and other medical conditions. Never assume you know which parasite is responsible without appropriate veterinary advice.
Fleas in dogs
Fleas are small, blood-feeding insects that can cause considerable discomfort.
A dog with fleas may scratch repeatedly, bite at its coat, develop sore patches or experience hair loss. Some dogs develop flea allergy dermatitis and can react strongly even to a small number of bites.
How to check for fleas
Use a suitable flea comb, paying attention to the base of the tail, back, belly and neck.
Look for moving fleas or small black specks.
If you find black specks, place them on damp white tissue. Flea dirt may leave reddish-brown marks because it contains digested blood.
However, not finding fleas doesn’t necessarily rule out an infestation.
Why treating the dog alone may not work
Fleas can lay eggs that fall into carpets, bedding and other areas around the home.
When a household infestation develops, veterinary advice may include suitable treatment for the affected animals alongside cleaning measures.
Regular vacuuming and washing suitable pet bedding can help.
In homes with both dogs and cats, product safety is particularly important.
Never use dog flea treatments on cats. Some contain permethrin, which can be fatal to cats.
For further information, see the PDSA guide to parasites in dogs.
Ticks: What to look for after a walk
Ticks attach to the skin and feed on blood.
You can find them in woodland, heathland, long grass, and other vegetation. Dogs walking in these environments may be exposed, particularly where wildlife such as deer is present.
Ticks can also carry infections, including Lyme disease.
Where should you check?
After walks through suitable tick habitats, examine:
- Around the ears and head.
- The neck and collar area.
- Armpits.
- Belly and groin.
- Legs and paws.
- Between the toes.
A tick may resemble a small lump or skin tag. If you’re unsure what you’re looking at, ask your veterinary practice rather than pulling at it.
How to remove a tick safely
Use a suitable tick-removal tool and follow its instructions carefully.
Avoid squeezing or crushing the tick.
Never try to remove one by burning it, covering it in oil or petroleum jelly, or drowning it in a bath.
If you cannot remove it safely, contact your vet.
Once removed, monitor the site and seek veterinary advice if your dog becomes unwell or develops concerning symptoms.
Worms in dogs
Several types of internal worm can affect dogs.
Some live in the digestive system, while others affect different organs.
Roundworms
Roundworms are especially important in puppies, which may acquire infection from their mother.
Possible signs include poor growth, a swollen abdomen, digestive upset or visible worms, although some infections cause few obvious symptoms.
Roundworm eggs can also contaminate soil.
Picking up dog faeces promptly and maintaining good hygiene help reduce the risk to other animals and people.
Tapeworms
Tapeworm segments can resemble small grains of rice.
You might notice them around your dog’s bottom, in faeces or on bedding.
Certain tapeworms are transmitted when dogs swallow infected fleas, while others may be associated with eating infected animal material.
This is one reason flea prevention and worm prevention should be considered together.
Lungworm
Lungworm is a particularly important parasite because it can cause serious illness.
Dogs can acquire the common UK lungworm, Angiostrongylus vasorum, by swallowing infected slugs or snails.
This may happen directly or accidentally while exploring vegetation, drinking from outdoor bowls or investigating items left in the garden.
Possible symptoms include:
- Coughing.
- Breathing difficulties.
- Reduced energy or exercise tolerance.
- Unexplained bruising or bleeding.
- Weight loss.
- Weakness or collapse.
Some dogs show less obvious symptoms, and other illnesses can cause similar signs.
Lungworm cannot be reliably identified simply by looking for visible worms in faeces.
Diagnosis requires veterinary assessment and may involve specialised testing.
Not all general worming products protect against lungworm, so ask your vet whether your dog’s prevention plan covers the risks relevant to them.
Seek urgent veterinary help for breathing difficulty, unexplained bleeding, seizures or collapse.
Mites and mange in dogs
Not all mites cause the same problems.
Sarcoptic mange
Sarcoptic mange is caused by mites that burrow into the skin.
It can cause severe itching, redness, crusting and hair loss. It is contagious between dogs and requires veterinary treatment.
Demodex mites
Demodex mites can naturally occur on dogs without causing problems.
However, excessive mite populations can lead to skin disease, particularly in young dogs or dogs with underlying health issues.
Signs may include patches of hair loss, redness and skin inflammation.
Demodex is not the same condition as sarcoptic mange, and treatment decisions should be based on veterinary diagnosis.
Ear mites
Ear mites may cause intense scratching, head shaking and dark ear discharge.
However, ear infections, allergies and foreign objects can cause similar symptoms.
Do not put household remedies or unprescribed treatments into your dog’s ears.
A vet can establish the cause and recommend appropriate care.
Harvest mites: A seasonal problem
Harvest mites are especially common in late summer and autumn.
You may encounter these tiny orange mites in grassy or wooded areas.
Affected dogs may repeatedly lick their paws, scratch or develop small irritated areas.
I pay particular attention to paws and lower legs after walks through vegetation in autumn.
If you suspect harvest mites, contact your vet rather than applying additional parasite products without advice.
Choosing a suitable parasite prevention plan
It can be tempting to buy a flea or worm product and assume the dog is protected against everything.
Unfortunately, it isn’t always that simple.
Different products cover different parasites.
The most appropriate plan depends on factors including:
- Age, breed, weight and health.
- Previous parasite problems.
- The dog’s local environment.
- Travel and imported-dog history.
- Scavenging or hunting behaviour.
- Contact with other animals.
- Swimming and bathing habits.
- Other medication and previous reactions.
Your vet or suitably qualified pet-medicine professional can advise which products are appropriate.
The European Scientific Counsel Companion Animal Parasites (ESCCAP UK & Ireland) provides guidance on parasite risks and control.
Be cautious with home remedies
I would not recommend treating parasites with garlic, essential oils, vinegar, or homemade sprays.
Natural does not automatically mean safe.
Some ingredients can harm pets, and ineffective treatment may let the underlying problem worsen.
Always seek appropriate professional advice.
Consider the environment too
Some parasite medicines contain substances that can harm aquatic life if they enter rivers or streams.
When using topical products, follow their bathing, swimming, application, and disposal instructions carefully.
Do not wash unused treatment down the sink or allow dogs into natural water during any specified restriction period.
Your vet can discuss an appropriate prevention plan that balances the dog’s needs with environmental considerations.
My practical post-walk parasite checklist
After walking through woodland, heathland or long grass, I recommend taking a moment to check your dog.
- Look around the ears, face and neck.
- Check beneath the collar or harness.
- Run your hands gently over the body.
- Examine the belly and armpits.
- Check paws and between the toes.
- Look for unfamiliar lumps or attached ticks.
- Notice unusual scratching, licking or discomfort.
- Contact your vet if you find something concerning.
You don’t need to turn every walk into a medical examination.
The aim is to become familiar with what is normal for your dog so that changes are easier to notice.
What I watch for during solo dog walks
As a dog walker, I am not responsible for diagnosing or treating parasites.
However, I do watch for changes that may be worth reporting to an owner.
These include unusual scratching, repeated paw licking, visible ticks, digestive upset or a sudden change in how comfortably a dog moves.
If I notice something concerning, I can report it, provide a photograph where appropriate and recommend that the owner seeks veterinary advice.
My one-to-one approach also means I can adapt routes when a dog is particularly sensitive to certain environments.
You can read more about my Solo Dog Walks in Finchley and Muswell Hill.
When should you contact your vet?
Contact your vet if you notice persistent itching, hair loss, sore skin, visible fleas or worms, suspected mites, digestive problems or unusual weight loss.
Also contact them if your current parasite prevention appears ineffective or you are unsure which products are suitable.
Seek urgent veterinary help if your dog experiences:
- Difficulty breathing.
- Collapse.
- Seizures.
- Unexplained or significant bleeding.
- Severe weakness.
- Rapidly worsening symptoms.
These signs are not necessarily caused by parasites, but they require prompt assessment.
For wider health and emergency information, visit my Dog Health and First Aid Guide.
Frequently asked questions
Can dogs get fleas in winter?
Yes. Fleas can survive and reproduce inside heated homes, so they are not exclusively a summer problem.
Do all dogs need the same worming schedule?
No. Parasite prevention should reflect an individual dog’s age, lifestyle, health and exposure risks. Your veterinary practice can advise on an appropriate plan.
Can I see lungworm in my dog’s poo?
You cannot reliably detect lungworm by looking for visible worms. Your vet may recommend specific diagnostic tests if lungworm is suspected.
Can my dog catch parasites from other dogs?
Some parasites can spread through contact with infected animals or contaminated environments. Transmission depends on the parasite involved.
Can a dog have parasites without symptoms?
Yes. Some infections cause few obvious signs, particularly in their earlier stages.
Should I treat my dog again if the first product doesn’t work?
Not without professional advice. Repeating or combining treatments can be harmful. Your vet can investigate why the problem persists.
Final thoughts
Parasite prevention is part of responsible dog care, but it doesn’t need to be complicated or frightening.
For most owners, the important steps are straightforward: get suitable veterinary advice, follow an appropriate prevention plan, keep the home and environment clean, pick up after your dog and check for anything unusual.
One of the benefits of spending time with dogs every day is becoming familiar with their normal behaviour.
Sometimes a change in scratching, movement or energy is the first indication that something needs checking.
And when in doubt, I would always rather an owner asked their vet than relied on guesswork.
Useful veterinary references
- PDSA: Parasites in Dogs
- ESCCAP UK & Ireland: Parasites
- ESCCAP: Veterinary Parasite Control Guidelines
Originally published March 2016. Updated August 2026 and reviewed October 2026.
F
