Why Is My Dog So Itchy? 8 Common Causes and What to Do
Last updated: 23 September 2026
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All dogs scratch now and then. But if your dog is scratching, licking, chewing or rubbing more than usual, something is irritating their skin. The good news is that most causes are common and treatable once you know what you’re dealing with.
The quick answer: the most common reasons a dog is itchy are fleas, allergies to things in the environment (such as pollen, grass or house dust mites), and food allergies. Mites, skin infections and irritants like shampoos or cleaning products are the next most likely causes. In the UK, harvest mites are a common cause of sudden itchy paws in late summer and autumn.
Where your dog is itchy, and when it started, are the best clues to the cause.
Call your vet straight away if your dog has:
- Swelling of the face, lips or eyes
- Hives (raised lumps) spreading across the body
- Difficulty breathing, wheezing or noisy breathing
- Sudden vomiting or diarrhoea alongside itching or swelling
- Weakness or collapse
These can be signs of a severe allergic reaction, which is an emergency. If your own vet is closed, contact your nearest out-of-hours emergency vet.
In this guide
- Where is your dog itchy? A quick guide
- 1. Fleas and flea allergy
- 2. Environmental allergies
- 3. Food allergies
- 4. Harvest mites
- 5. Mange (mites)
- 6. Skin infections and hot spots
- 7. Contact irritation and dry skin
- 8. Other causes worth knowing about
- Can Piriton help an itchy dog?
- Tip: keep an itch diary
- Frequently asked questions
Where is your dog itchy? A quick guide
| Where the itch is | Other signs | Most likely cause |
|---|---|---|
| Lower back and base of the tail | Small scabs, hair loss, black specks in the coat | Fleas or flea allergy |
| Paws, face, ears, armpits, belly | Worse in spring and summer, or all year round | Environmental allergies |
| Ears and paws, often all year | Loose stools, wind or recurring ear infections | Food allergy |
| Paws, legs, belly, ear edges | Tiny orange dots, late summer to autumn | Harvest mites |
| Ear edges, elbows, belly | Intense, sudden scratching; people in the house may get itchy spots too | Sarcoptic mange |
| One wet, red, weeping patch | Appeared quickly, often painful | Hot spot (skin infection) |
| All over, with a greasy coat | Sour or yeasty smell | Yeast infection |
| Where the body touches the floor or bedding | Started after a new product | Contact irritation |
Fleas or flea allergy
Where: Lower back and base of the tail
Signs: Small scabs, hair loss, black specks in the coat
Environmental allergies
Where: Paws, face, ears, armpits, belly
Signs: Worse in spring and summer, or all year round
Food allergy
Where: Ears and paws, often all year
Signs: Loose stools, wind or recurring ear infections
Harvest mites
Where: Paws, legs, belly, ear edges
Signs: Tiny orange dots, late summer to autumn
Sarcoptic mange
Where: Ear edges, elbows, belly
Signs: Intense, sudden scratching; people in the house may get itchy spots too
Hot spot (skin infection)
Where: One wet, red, weeping patch
Signs: Appeared quickly, often painful
Yeast infection
Where: All over, with a greasy coat
Signs: Sour or yeasty smell
Contact irritation
Where: Where the body touches the floor or bedding
Signs: Started after a new product
These are patterns, not a diagnosis. Many itchy dogs have more than one thing going on, for example a flea allergy on top of a pollen allergy.
1. Fleas and flea allergy
Fleas are the most common cause of itchy skin in dogs, and they are a problem all year round because they thrive in centrally heated homes. Some dogs are allergic to flea saliva, so a single bite can set off days of intense itching. That’s why a flea-allergic dog can be very itchy even when you can’t find a single flea.
Signs to look for: scratching and chewing around the lower back, base of the tail and back legs. Small red bumps, scabs or thinning fur in the same area.
How to check: stand your dog on a white towel or sheet of kitchen roll and comb through the fur on their back and the base of their tail with a fine flea comb. Tip any black specks onto damp white paper. If they spread into reddish-brown streaks, that’s flea dirt (digested blood), and you have fleas.
What to do:
- Treat every dog and cat in the house, not just the itchy one.
- Treat your home. Only a small share of the flea population lives on your pet. Most of it is eggs, larvae and pupae in carpets, bedding and sofas.
- Wash your dog’s bedding and throws on a hot wash (60°C).
- Keep up treatment every month, even in winter. Flea eggs can lie dormant in the home for months.
- If your dog’s skin is broken, infected or very sore, see your vet. They may need medication to settle the skin.
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2. Environmental allergies (atopic dermatitis)
After fleas, allergies are one of the most common reasons for itchy skin. Environmental allergy (vets call it atopic dermatitis or atopy) means your dog’s immune system overreacts to things they breathe in or touch, such as grass and tree pollen, house dust mites or moulds. Most allergic dogs react to more than one thing. It often starts in young dogs, and breeds such as West Highland White Terriers, Bichon Frises, Golden Retrievers and French Bulldogs are more prone.
Signs to look for: licking and chewing the paws, rubbing the face on the carpet, scratching the armpits and belly, red skin, and repeated ear infections. Pollen allergies tend to flare in spring and summer. Dust mite allergies can be worse in winter when the heating is on.
What to do:
- See your vet. Allergies can’t be cured, but they can be managed well. Vets now have several effective prescription anti-itch medicines, and allergy testing with immunotherapy is an option for some dogs.
- Rinse or wipe your dog’s paws and belly after walks in long grass during pollen season.
- Wash bedding weekly and vacuum regularly.
- Avoid sprays, air fresheners and scented products around your dog.
- Keep flea treatment up to date. Allergic dogs are often extra sensitive to flea bites.
- Consider adding omega-3 fatty acids (fish oil) to their diet. Vets often recommend them as part of looking after allergic skin, alongside other treatment. They support the skin’s natural barrier, but they won’t replace medication for a dog with a lot of itching.
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A pump bottle of Scottish salmon oil that you add to your dog’s food. It’s an easy way to add omega-3 fatty acids to support healthy skin and coat. Check the feeding guide for your dog’s weight, and tell your vet if your dog is on other medication.
3. Food allergies
Some dogs are allergic to an ingredient in their food, most often a protein such as beef, chicken or dairy. It can develop even after years on the same food. Food allergy is less common than flea or environmental allergy, but it’s worth considering if the itching happens all year round.
Signs to look for: itchy ears and paws, recurring ear infections, and sometimes tummy trouble such as loose stools or wind. The itching doesn’t follow the seasons.
What to do:
- Talk to your vet about a food trial. This is the only reliable way to diagnose a food allergy. Blood and hair tests sold online are not accurate.
- A food trial means feeding only a special diet (usually a prescription hydrolysed or novel-protein food) for 6 to 12 weeks (your vet will advise how long), with nothing else. No treats, chews, dental sticks or table scraps.
- Switching from one supermarket brand to another usually isn’t enough, because many foods share the same ingredients.
If your dog’s itching keeps coming back whatever you try, a vet check is the best next step. Allergies and secondary skin infections often need prescription treatment to break the cycle.
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Freeze-dried salmon treats with added marine collagen, designed to support skin and coat condition. They’re made with salmon as the protein. If your dog is on a food trial, check with your vet before giving any treats.
4. Harvest mites
Harvest mites are tiny orange mite larvae that live in long grass, fields, woodland edges and gardens. In the UK they are most active from late summer into autumn. They climb onto dogs as they walk through vegetation and feed on the skin, which causes intense irritation.
Signs to look for: sudden itching of the paws, legs, belly, armpits and ear edges after walks. Look closely, especially between the toes, and you may see clusters of bright orange dots.
What to do:
- See your vet. There are no products specifically licensed for harvest mites in the UK, but your vet can recommend a suitable treatment and settle the itch.
- During the season, check your dog’s paws and belly after walks and rinse their feet with warm water.
- Walk in the early morning or evening where you can, and avoid long grass in the heat of the day.
- Contact your vet immediately if your dog develops vomiting, diarrhoea, trembling or severe tiredness after a woodland walk in autumn. This can be a sign of seasonal canine illness, which is rare but serious.
5. Mange (mites)
Two types of mite cause mange in dogs:
- Sarcoptic mange (scabies) causes intense, relentless itching, often starting on the ear edges, elbows and belly. It’s contagious to other dogs and can give people in the household itchy red spots.
- Demodectic mange is caused by mites that live on most dogs harmlessly. It tends to cause patchy hair loss, usually in puppies or dogs with a weakened immune system, and is often less itchy.
What to do: see your vet. Mange needs a proper diagnosis (usually a skin scrape) and prescription treatment. Treat all dogs in the household if your vet advises it.
6. Skin infections and hot spots
Bacteria and yeast live on all dogs’ skin without causing problems. When the skin is damaged by scratching, allergies or moisture, they can overgrow and cause an infection, which makes the itching worse.
Signs to look for:
- Hot spots: a red, wet, weeping patch that appears very quickly, often on the neck, face or hips. Usually painful.
- Bacterial infection: red spots, pimples, crusty rings or scabs, sometimes with a smell.
- Yeast infection: a greasy coat, a sour or musty smell, darkened skin, and itchy paws or ears.
What to do: see your vet. Infections usually need medicated shampoo, creams or tablets, and your vet will want to find what triggered the infection in the first place.
7. Contact irritation and dry skin
Some dogs react to things that touch their skin, such as a new shampoo, washing powder, carpet cleaner, floor cleaner or certain plants. Dry skin can also be itchy, particularly in winter with the heating on or if a dog is bathed too often.
Signs to look for: redness and itching mainly on the belly, paws, armpits and chin, where there’s less fur and the skin touches the floor. It often starts after something new comes into the house.
What to do:
- Think about what changed recently and switch back if you can.
- Rinse bedding thoroughly and use a non-bio, fragrance-free detergent.
- Only bathe your dog when needed, using a gentle shampoo made for dogs.
8. Other causes worth knowing about
- Ear infections: head shaking, scratching at the ears, a smell or discharge. See your vet.
- Anal glands: scooting along the floor or licking under the tail usually points to the anal glands rather than itchy skin.
- Boredom or anxiety: some dogs lick or chew the same spot out of habit or stress, which can cause a sore patch called a lick granuloma.
- Hormone problems: conditions such as an underactive thyroid can cause thinning fur, flaky skin and repeated skin infections, usually alongside weight gain and low energy.
Can Piriton help an itchy dog?
Piriton (chlorphenamine) is an antihistamine that vets sometimes suggest for mild allergic itching, bites or stings. It can take the edge off itching for some dogs, but antihistamines tend to work less reliably in dogs than in people, and they don’t treat the cause. They won’t clear fleas, mites or infections.
Only give Piriton if your vet has said it’s suitable for your dog, and never use products that contain other ingredients, such as decongestants. Dogs that need regular relief usually do better on one of the prescription anti-itch medicines your vet can offer.
Checking a Piriton dose?
Use our Piriton dosage calculator for dogs to see the typical dose range by weight, then confirm with your vet.
Tip: keep an itch diary
If your dog’s itching comes and goes, keep a simple diary for a few weeks. Note where they scratch, how bad it is on a scale of 0 to 10, where you walked, what they ate and any new products at home. Take dated photos of any red or sore patches. Patterns such as “worse after the park” or “worse in May” make it much easier for your vet to pin down the cause.
Frequently asked questions
Why is my dog itchy but has no fleas?
Your dog may still have fleas even if you can't see any, because flea-allergic dogs groom so much that they remove the evidence. Try the damp paper test described above. If there's no flea dirt, the next most likely causes are environmental allergies, food allergies, mites or a skin infection, and your vet can help work out which.
Why is my dog so itchy at night?
Itching often seems worse at night because there are fewer distractions, so your dog focuses on the itch and you're more likely to hear it. A warm bed can also make itchy skin feel worse, and dust mite allergies can flare in bedding. Washing bedding weekly at 60°C can help.
Is it normal for a dog to scratch every day?
A bit of scratching is normal, especially after a walk, a nap or during moulting. It's worth a closer look if your dog is scratching often enough to disturb their sleep or yours, or if you see red skin, scabs, bald patches, a smell or broken skin.
Why is my dog suddenly so itchy in autumn?
In the UK, harvest mites are a common cause of sudden itching from late summer into autumn, especially on the paws, legs and belly after walks in long grass or woodland. Look for clusters of tiny orange dots between the toes. Fleas also tend to peak in autumn as homes warm up.
Can I give my dog Piriton for itching?
Vets sometimes recommend Piriton (chlorphenamine) for mild itching, bites or stings, but it doesn't suit every dog and it doesn't treat the cause of the itch. Check with your vet first, use plain Piriton tablets with no added ingredients, and see your vet if the itching lasts more than a few days.