Why is My Dog Constantly Scratching
- Dr Simon Want BVM&S CertVD MRCVS RCVS
- Feb 26
- 10 min read
If your dog is itchy it may be constantly, or at least regularly, scratching itself you may be feeling worried and anxious. You may have sought treatment but it has either not worked or your dog’s scratching may have returned, or even got worse. Perhaps you are now feeling upset, frustrated or even angry. Perhaps you are being kept awake at night by your dog’s constant scratching.
As mentioned, scratching is a sign that your pet is itchy. However, licking, biting, shaking the ears and rubbing can also be signs that your pet is itchy. It is not your fault and certainly not your pet’s. The commonest causes are allergies, parasites and secondary infections.
In this article we’ll discuss:
Why Is My Dog Constantly Scratching And Biting Themselves?
The symptoms associated with itching are very common in dogs and may affect most areas of the body. However, common areas affected could be the ears, face, paws, legs, tummy and the skin around the anus. Dogs may scratch their sides and less commonly their backs too. More commonly though they will rub their face, shake or scratch their ears, bite or lick their paws, nails, legs, tummy and skin around their tail or anus.
Allergies and parasites make up the majority of these cases and are often accompanied by secondary infections that make them even more itchy. Symptoms can worsen over time. Some dogs may be constantly itchy but others may be worse at certain times of year, such as with a pollen allergy.
What Causes A Dog To Itch Excessively?
The main causes of your dog’s excessive itch include parasites, allergies or infections.
Parasites include:
Fleas - common in dogs
Lice - more common in puppies
Ear mites - seen in dogs, especially young animals
Mange mites
Sarcoptic mange in dogs
Surface mites - Cheylettiella
Demodex mites
Harvest mites
Allergies in dogs include:
Atopic dermatitis - airborne allergens include pollen and house dust mites
Flea allergic dermatitis - this is distinct to fleas as the dog is now allergic to the bite of the flea
Infections include:
Ringworm (dermatophytosis) - a primary fungal infection of the skin
Pyoderma - secondary bacterial infection - often seen with allergies
Malassezia dermatitis - a naturally occurring yeast on the skin of dogs that can proliferate and cause a secondary infection
You may notice symptoms such as:
Red skin, feet and ears
Spots - sometimes red and sometimes yellow
Crusty or flakey skin. This can be due to bacterial infection as well
Hair loss (alopecia)
Scratch marks
Greasy residue on the lips or feet due to Malassezia
Discharge from the ears - this could be brown and greasy or pussy
Why Is My Dog Scratching Constantly But Has No Fleas?
Fleas are only one cause of scratching and there are many more. A number of parasites cannot be seen with the naked eye and tests may need to be done to find them.
Allergies are due to microscopic things in the air that land on the skin and illicit itchiness, such as pollen or house dust mites.
If your pet is food allergic it may be the proteins in its food. The commonest proteins are chicken, beef and dairy but it really does depend on your pet’s individual diet.
The secondary infections that cause itchiness in allergic patients is often due to overgrowth of the pet’s own, normal yeast or bacteria.
If you regularly use anti-flea medication, especially from your vet, then fleas are even more unlikely and you should see your own vet first to see if a diagnosis can be found and treatment initiated.
Are There Any Breed-Specific Skin Problems That Make Some Dogs Scratch More?
Some breeds are genetically predisposed to atopic dermatitis and food allergy.
Common breeds affected are:
Labrador retrievers
Golden retrievers
Cocker spaniels
Cockapoos
Cavapoos
French bulldogs
British bulldogs
Pugs
Cavalier King Charles spaniels
West Highland white terriers
German shepherd dogs
As you can see these really are the popular breeds and they are all statistically more likely to suffer itchy skin and ears due to allergic skin disease. It has been proven that atopic dermatitis is genetically passed on and it is now thought that up to 20% of dogs may have allergic skin disease.
“In my practice I see all of the above dog breeds regularly but I feel Labradors, Frenchies and Cockapoos seem to be very much over represented.” Dr Simon Want
Common Skin Conditions Causing Dog Itching
Allergic skin and ear disease is by far the most common condition leading dogs to itch.
For some reason it is assumed that ear disease is a separate condition and that head shaking and scratching of the ears may be separate to more generalised itchy skin or licking of the paws. This is not true. The most common cause is allergy and some dogs may be itchy in some, or all, of the commonly affected sites.
Alternatively, your dog may present with a left sided ear problem one month, the right another time and possibly biting its feet during another allergic flare up. The condition can wax and wane and may be seasonal or present at any time of year. In fact, a dog with house dust mite allergy may be worse in the winter when it is indoors more and the central heating is on. A pollen allergic dog will flare during the season when the offending pollen is present. Trees may pollinate from February or March, grasses throughout the summer and weeds can pollinate into autumn.
Food allergic dogs are often itchy throughout the year.
How Many Dogs are Affected by Allergies?
Within allergic skin disease, dogs can have food allergy, atopic dermatitis or both and the symptoms are identical.
Atopic dermatitis 50% of dogs
Food allergy exclusively 10% of dogs
Both atopy and food allergy 40%of dogs
Symptoms to Look Out For
The skin can only react in a handful of ways which is why it is so important to get an accurate diagnosis as to the underlying cause of the symptoms.
As we know symptoms include:
Red skin, feet and ears
Spots - sometimes red and sometimes yellow
Crusty or flakey skin. This can be due to bacterial infection as well
Hair loss
Scratch marks
Greasy residue on the lips or feet due to Malassezia
Discharge from the ears - this could be brown and greasy or pussy
Parasites Causing Dogs to Scratch
Parasites can cause itchy skin and it can look just like the symptoms we see with allergic skin disease. The main alternative diagnosis to allergic skin disease is scabies, caused by the mite, Sarcoptes scabiei.
Can Anxiety Or Stress Cause A Dog To Scratch Excessively?
It would be rare for anxiety or stress to be the primary problem causing your dog to scratch excessively, however, the itching can induce anxiety and behaviour changes within your pet. It may make your dog shy away from contact when they are uncomfortable and they may actively try to avoid certain treatments, such as ear cleaners or ear medications, possibly due to previous painful ear infections.
Sometimes anxiety can make the condition worse so it is important to talk about this with your pet dermatologist.
Marla's story
Marla was seen with red, inflamed, painful skin and many pustules. Her symptoms were caused by a mite called Demodex canis which was found via skin scraping. The close up image of the mite is from Simon's microscope, which he showed to Marla's owner before starting treatment.
The pictures below show the difference in Marla's condition just 4 weeks after starting treatment at Advanced Veterinary Dermatology.
When Should I Take My Scratching Dog To The Vet?
If your pet is scratching, biting, licking, rubbing or grooming itself more than you would expect to see with normal grooming behaviour then it is itchy. This is a symptom of an underlying problem and needs an accurate diagnosis to successfully manage and hopefully cure the problem.
In the first instance if you cannot find the source of the problem yourself and resolve it then contact your normal GP vet. Hopefully, they can make a diagnosis and offer treatments that are successful and either cure the problem or manage it sufficiently well.
If your vet cannot make a diagnosis or successfully treat the problem, if it is becoming increasingly recurrent or getting worse then you would talk to them about a consultation with a veterinary dermatologist.
They may have someone they refer to already but you are free to request to be referred to a specific dermatologist and you may also seek your own second opinion.
You can contact us at Advanced Veterinary Dermatology to discuss your pet’s problem or make an appointment.
How To Stop A Dog From Scratching All The Time
To stop your dog from scratching themselves you should contact your vet or a pet dermatologist. They can diagnose and control secondary infections with topical shampoos, foams and sprays, creams and gels or tablets. They may be able to improve the skin barrier using topical therapy and essential fatty acid supplements.
To top the itch you can reduce the itchy sensation with anti-itch medications available from your veterinary dermatologist and GP vet, such as:
Antihistamines
Corticosteroids
JAK inhibitors - Apoquel® & Zenrelia®
Monoclonal antibody injections - Cytopoint®
Calcineurin inhibitors - ciclosporin - Atopica®, Cyclavance® and Sporimune®
To help desensitise your pet a veterinary dermatologist may recommend using immunotherapy injections (‘allergy shots’) following allergy testing. You should avoid allergens when possible, especially if your dog has a food allergy.
Treatment depends, as always, on the underlying primary diagnosis and the presence of any secondary bacterial or yeast infections.
Are There Any Home Remedies I Can Try To Stop My Dog Scratching?
At home you can help your dog by washing them regularly with anti-allergy shampoos to help wash off potential allergens and reduce infections.
Reduce house dust mite exposure by regularly vacuuming using a machine with a HEPA filter. Wash bedding weekly at 60 degrees. Purchase anti-dust mite bedding e.g. Vetbed Gold®. Spray carpets and soft furnishings with a product called Allergone® that coats the mites and makes them not be allergic to your pet.
There are also little mites in commercial dog food called storage mites. We can also find these in our foods, such as dried pasta and cheese. These can cause allergy in a similar way to house dust mites so avoid feeding the grainy bits of food at the bottom of the bag. Put food in a bin and wash out between bags. Wipe your dog's face after eating with a damp flannel.
Are There Any Dietary Changes To Reduce Dog Scratching?
Food allergy can be seen in up to 50% of allergic dogs. 10% will have only a food allergy and the other 40% both food allergy and atopic dermatitis.
As a result of this it is very important that you and your vet perform an elimination diet trial to know if food allergy is present or not. It can be hard to be sure, so you must deal with any secondary infections first and feed a hypoallergenic diet for 4 to 8 weeks, under the direction of your GP vet or veterinary dermatologist. At the end of the trial you will challenge your pet with its old food to see if it gets worse again.
Dogs are not gluten-intolerant so do not assume a grain-free diet will exclude food allergy. Beware what some manufacturers claim as not all ‘hypoallergienic’ diets are really hypoallergenic. As always get advice from your vet before picking a diet for an elimination diet trial.
During the diet trial you cannot feed any titbits at all and only offer water to drink. Make sure to stick to the agreed diet. At Advanced Veterinary Dermatology we often allow doggy peanut butter a treat as dogs are not allergic to peanuts. However, do not feed any peanut butter as many human versions contain something called xylitol, which is toxic to dogs.
There is a lot of cross-reactivity of proteins, such as chicken which can cross-react with duck and turkey but also fish. Beef can cross-react with lamb and dairy.
“I often recommend a hydrolysed diet as the proteins are broken down until they are so small that they cannot trigger an allergic response.” Dr Simon Want
Finally, we have NO RELIABLE blood tests for food allergies. Due to cross-reactivity results are often high even in normal dogs due to exposure of the proteins in their normal diet. This is why vets MUST perform an elimination diet trial.
What Are The Long-Term Health Effects Of Chronic Scratching In Dogs?
It is possible that the underlying causes of itching cause long-term chronic skin and ear changes that may be irreversible if not dealt with properly from the start.
Long-term health effects can include:
Thickened and pigmented skin in the body
More frequent skin and ear infections
Ulcerated ears with antibiotic-resistant infections
Perforated ear drums
Middle ear infections
Chronic pododermatitis and interdigital furunculosis - a painful swelling between the toes due to ruptured hair follicle and cysts. This requires long-term medication and possible ablation using a laser
At the time of writing laser ablation is only possible in three clinics in England. However, Advanced Veterinary Dermatology is one of those clinics.
Preventing Secondary Skin Infections From Dog Scratching And Licking
The most important thing here is an accurate diagnosis so that the primary underlying condition can be treated effectively. This is because most infections are secondary.
However, as part of an overall treatment plan anti-septic shampoos, spray and foams may be used to reduce infection.
Helping a Dog That Keeps Scratching
The most common causes of excessive dog scratching are parasites and allergies with secondary infections. It is important that an accurate diagnosis is achieved so that appropriate treatment can be initiated. Some conditions, such as scabies, can be cured, however, allergies often need life-long management.
Communication is key. I always say to owners with pets with allergies that, “allergy is not a life-threatening problem, but is a life-long problem”. Once we know this then it is easier to approach from a management point of view.
If you wish to make an appointment to review your pet’s skin condition or make a diagnosis and initiate appropriate treatment then contact us. We have over 30 years experience as a veterinary surgeon and nearly 20 years as a veterinary dermatologist.
Sources and References:
Behavioural Differences in Dogs with Atopic Dermatitis Suggest Stress Could Be a Significant Problem Associated with Chronic Pruritus by Naiomi D. Harvey et al
Current Knowledge on Canine Atopic Dermatitis by Outerbridge and Jordan
Clinical Signs and Diagnosis of Feline Atopic Syndrome: Detailed Guidelines for a Correct Diagnosis by Santoro et al
Written and Approved by:
Dr Simon Want BVM&S CertVD MRCVS
RCVS Advanced Practitioner in Veterinary Dermatology
Director of Advanced Veterinary Dermatology Ltd
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