Itchy Dogs

Dogs very commonly present to vets for itchy skin. There are 3 main reasons for dogs to scratch; infection, ectoparasites and skin allergies, and often a combination of conditions occur. Skin allergies are generally a lifelong condition needing ongoing treatment. Thus owners and vets are looking for treatment options which are less likely to have side effects.

Disclaimer: This information is intended for dog owners living in the Republic of Ireland.

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  • Owning a dog with a severe allergic itch problem can be upsetting and frustrating for the whole family, not to mention distressing for your beloved pet.

    Depending on the cause of the allergy, some dogs itch all year round and some only itch at certain times of the year. Either way, it would be great if we could switch off that itch!

    Innovative and effective therapies are available to ensure that neither the dog nor family need suffer as a result.

    You could become frustrated that nothing seems to work but treatments and solutions are available to treat your dog.

  • Dogs, just like people, can show symptoms of allergy when their immune systems recognise certain everyday substances as foreign. Even though these substances are harmless to most animals, a dog with allergies will have an extreme reaction to them. The skin is one of the most common organs to show symptoms of allergy.


    • Red, itchy skin
    • Increased scratching
    • Chewing, especially around the base of the tail and paws
    • Itchy ears and recurring ear infections
    • Constant licking

    Dogs with an allergic skin condition may also suffer from skin infections, which may cause hair loss, scabs or crusts on the skin

  • A few common allergies include

    • Various Types of Pollen
    • Tree Bark
    • House Dust Mites
    • Fungal Spores
    • Flea Bites
    • Grasses
    • Proteins in Food

    There are many others and your vet may need to run a number of tests to find out the true cause of the allergy.

  • Fast relief from itching


    • Starts to work within the first few hours

    • Reduces the redness and soreness caused by scratching



    • Can be used for short term (seasonal or acute) allergies and longer term (ongoing) allergies

    • No interruption of other vital medications your dog may need

    • Doesn't interfere with important tests your vet may run to determine the cause of the itch



    • Infrequent unwanted or inconvenient side effects

    • Simple daily medication

    • Easy to give, with or without food

  • Itchy dogs are seen daily in all veterinary practices, particularly when ears are considered part of the dog's skin. Itchiness affects a dog’s quality of life, as it can interrupt sleep, playtime and everything in between. Resultant scratching damages the skin, and often results  in secondary infections which then exacerbate the original condition.


    There are a number of different reasons for your dog to start itching. And to further complicate matters your dog may itch due to one or multiple reasons at any given time, and the cause may change, for example if a complicating secondary infection occurs on top of an already existing allergy.

    • Fleas are a very common cause of itch and regular treatment with effective products of all pets in the household is the best way to treat and prevent flea infestations. Fleas can multiply very quickly, often causing massive household infestations. A 2005 a UK study showed that almost half of owners were unaware of their pet’s flea infestation. This may be because some pets tolerate fleas without showing any clinical signs, while in others just a few fleas cause severe itchiness. This is discussed further in the Flea Allergic Dermatitis section below.
    • Sarcoptic mites cause sarcoptic mange, which is an extremely itchy condition. The mites are very contagious and easily passed from one dog (or even fox) to another. Without treatment the disease can become incredibly severe, with generalised hair loss and an angry red rash. Mites can also be transmitted from dog to owner.
    • Ear mites are very common, particularly in puppies and as the name suggests they generally live in the ear canal. Some pets may have ear mites but show no clinical signs and act as a source of re-infestation for their housemates. Signs such as head shaking, ear scratching, presence of a waxy discharge or pain may suggest your pet has an ear mite infestation.
    • Other parasites such as lice, cheyletiella and demodex mites, although less common, can cause itchiness and should be ruled out when investigating the cause(s) of itchy skin disease.

    Fortunately there are   many effective treatments available for these different ectoparasites, however not all products have the same efficacy. Your veterinary surgeon will recommend the best product for your dog.

    Infectious skin disease
    • Bacterial skin infections are extremely common but almost always occur secondary to another problem, very often but not exclusively allergies, which are discussed further below. Although antibiotics are often required, shampoos and topical ointments can also be effective in both treating and minimising repeat infections. Your vet will discuss the best option for your dog’s condition depending on the type of bacteria involved and the extent of the infection. An investigation into the underlying cause of the problem should be done to prevent recurrence.
    • Yeast infections are often due to a species called Malassezia which can be found on the skin of normal dogs. It causes disease when overgrowth of the yeast occurs. This can happen in dogs with excessive skin folds (due to breed, anatomy or obesity), and dogs with underlying issues such as allergies or a compromised immune system. Clinical signs are non–specific (so may be caused by other diseases) but may include itching, redness,greasiness, waxiness, scaling, dark pigmentation and thickened bald skin with or without an odour. White or pale hair can be stained brown by the yeast.


    Allergies are most likely inherited and occur because the dog’s immune system recognises a substance (an allergen) as foreign and in response itching and an inflammatory reaction occurs. 

    Flea Allergic Dermatitis*(FAD)

    Flea Allergic Dermatitis (FAD) is the most common allergic disorder of dogs (and cats). The ‘allergen’ is a protein in the flea’s saliva. Allergic pets can be extremely itchy even in the presence of only a few fleas that often prove difficult to find.

    These dogs also show signs of inflammation, such as redness and hair loss, in front of the tail head and on the back of the thighs with signs quickly extending elsewhere.

    Your veterinary surgeon will look for signs of a flea infestation when he/she suspects FAD, although FAD cannot be completely ruled out if no fleas are found. An effective flea control program should be instigated in all suspect cases. Many dermatologists recommend a minimum treatment period of 6 months before FAD can be ruled out.

    *Dermatitis: medical term describing inflammation of the skin

    Food Allergic Dermatitis

    Food allergens are ‘normal’ animal and vegetable proteins, such as dairy, meat or wheat products, causing an allergic response in certain dogs.

    Generally signs are seen all year round. Itchiness is normally the first sign seen, and the inflammatory signs of redness and hair loss come slightly later.

    The only reliable way to diagnose food allergy is by doing a novel food trial. This involves feeding the dog a diet only containing ingredients which it has never been previously exposed to. The dog must not eat anything other than the diet (no treats, snacks or scavenging) during the trial period which may last 2 – 3 months.

    Although the thought of a food trial can be daunting for many owners, should it work, the dog’s signs may be largely controlled by dietary treatment alone, without the need for concurrent medication.

    Canine Atopic Dermatitis

    Canine Atopic Dermatitis (CAD) is a common disease with estimates of up to 10% of all dogs worldwide affected. It is an excessive immune response to environmental allergens such as tree, grass and weed pollens, moulds, house dust mites or animal dander. Very often dogs have more than one environmental allergic trigger.

    Latest research shows that allergens pass through the skin, and are not inhaled as was previously thought. The use of appropriate lotions, shampoos and foods, helps the skin to act as a physical barrier to these allergens. However, once inflammation occurs, the barrier function of the skin is damaged and the disease process can deteriorate very quickly.

    Typically dogs first show signs between the ages of 1 to 3 years. CAD may be seasonal, especially in the earlier years and/or if the allergy is due to environmental pollen. Signs and regularity of outbreaks get worse with age. The hallmark of CAD is marked itching without skin lesions. Signs may include itch and redness on the face, paws, axillae, ventrum (stomach) and ears. As a result of itchy behaviours secondary infections and secondary lesions such as hair loss, darkening and thickening of the skin can occur.

    Unfortunately there is no definitive diagnostic test for CAD; it is a diagnosis of exclusion, in other words it is diagnosed by ruling out all other causes of itchy skin disease, such as FAD, food allergy and sarcoptic mange.

    Intradermal tests and measurement of antibodies in the blood may be of assistance in identifying specific allergens but cannot be used to ‘diagnose’ CAD because many normal dogs also will have positive results.

    Contact Allergies

    Contact allergy is a rare skin disease of dogs caused by an allergic reaction following contact with a particular substance. Examples are plants, topical medications and shampoos, chemicals, products and materials used in the home. Typically signs occur in areas with little or no hair, such as the muzzle and ventral abdomen (under-carriage).


    Diagnosing the underlying reason for your dog’s itching is rarely straightforward. Some treatments offer a short term solution but if the underlying issue is not addressed the problem may return.

    Most skin diseases look the same; with redness and a rash. It is useful if the owner can inform the vet whether the itching or the rash appeared first. Factors such as the dog’s breed, its age when signs first appeared, and seasonality may offer additional clues.

    Although certain signs such as lesions on the ear margin (sarcoptic mange) may help the veterinary surgeon with making a diagnosis, generally a step-by-step approach is needed to rule out the different plausible diagnoses (ectoparasites, infection, allergies or a combination) in turn.

    In order to rule out ectoparasites your veterinary surgeon may perform tests such as a thorough coat combing and skin scrapes where the very outer layer of skin is examined for mites such as sarcoptes or demodex. As even small numbers may cause disease, it is usually recommended to perform a trial treatment irrespective of the test result.

    Bacterial and yeast infections can be identified by putting a sample on a slide, staining it and examining it under the microscope Occasionally a laboratory culture and sensitivity test may be required if there are concerns about the presence of certain bacteria.

    Once ectoparasites and infections are ruled out, allergies should be considered. As Flea Allergic Dermatitis is the most common allergy seen, flea control should be re-evaluated. Food allergies can only be diagnosed by doing a food trial, using a novel food source. It is only after having ruled out all of the above that a diagnosis of Canine Atopic Dermatitis can be assumed.


    Until recently, other than supplementary ectoparasite and infectious skin disease treatments, there were very limited treatment options for dogs with skin allergies available.

    Avoidance of the allergen is always recommended so if your dog is allergic to fleas, ensure flea control for all in-contact pets is optimal, and if your dog is allergic to a specific food, use alternative protein sources.

    Immunotherapy is the only treatment that offers the possibility of a cure for dogs with Canine Atopic Dermatitis and success rates between 50% and 90% have been reported. This involves preparing a specific vaccine for the dog which is given under the skin at intervals with an increasing concentration of allergen.

    Treatment of Canine Allergic Dermatitis generally involves a multimodal (using a variety of methods) approach to manage the disease and minimise clinical signs and secondary infections. As discussed earlier, using a food, shampoo or lotion will help keep the skin in good condition and allows it to act as a barrier against potential allergens. This is a useful management technique that may help to minimise the need for other medications.

    However, other medications are often needed to control the inflammation and itch seen in these dogs. As allergies are a disease of the immune system, all medications target this system in one way or another.

    • Steroids (e.g. prednisolone) are widely used to treat all types of Canine Allergic Dermatitis. They work quickly and can be very effective but, because they have numerous effects on many different organs in the body (not just the skin), side effects are commonly seen. In the short term your dog may be thirstier, hungrier or may urinate more often, which can be irritating if he/she is constantly begging or asking to go out to toilet at night. However, the long term effects are more concerning because of the effect steroids have on other parts of the body including the liver, the pancreas, the digestive system, the immune system and the adrenal glands. Lethargy and weight gain are common and recent research suggests that behavioural changes can occur. At lower doses these side effects may not be apparent but with long term treatment, as is common in these itchy skin cases, their appearance is inevitable. Steroids can also interfere with some diagnostic tests, vaccine performance and concurrent use of other medications.

    • Cyclosporine is another very effective immune-modulating drug, specifically licensed to treat the chronic (long term) signs of Canine Atopic Dermatitis. Compared to steroids, it is much more selective in the organs it targets, and so the long term side effects seen with steroids are largely avoided. Cyclosporine can be very effective in treating itch but it may take up to 8 weeks before clinical signs improve, and if an improvement is not seen by then, the treatment should be stopped. The most common side effects reported are vomiting and diarrhoea which are most often seen at the start of treatment and resolve in time without having to cease treatment. Unfortunately cyclosporine can also interact with other medications and treatment may need to be ceased prior to your dog’s annual booster.

    • Oclacitinib tablets are licensed to treat itch associated with Canine Allergic Dermatitis and clinical signs associated with Canine Atopic Dermatitis. It is a targeted treatment acting on an intracellular pathway involved in skin allergies. Oclacitinib has been shown to work as quickly as steroids without the short term side effects of increased thirst, hunger and urinating. As it is a targeted treatment, the long term effects on other organs are minimised. It does not affect diagnostic work up or interfere with vaccination and is safe to use with a range of other drugs. It is therefore suitable for cases which need both short or long term treatment.

      Lokivetmab is a monoclonal antibody which specifically neutralises Interleukin 31, a key protein messenger  which causes clinical signs in atopic  dogs. As it is an antibody, which is also a protein, it acts just like the dog’s own immune system and then are processed in exactly the same way as the dog’s own naturally produced antibodies. Lokivetmab is given by your vet as a monthly injection under the skin.

    Itchy skin disease negatively affects the quality of life of dogs and their owners. Affected dogs often lose interest in playing and wake their owners at night with sounds of licking, chewing and scratching. This constant itching and scratching can affect your dogs’ personality and even its relationship with you and your family.

    If ignored, the skin can become extremely itchy, red, scaly and irritated and if not treated, there is a risk of hair loss, skin infections and ear infections. Seeking early advice, pursuing appropriate diagnostic testing and exploring all treatment options therefore is extremely important.

    Although allergic skin disease is a life-long condition, working with your veterinary surgeon to identify the best treatment options for you and your dog will help control itch so you both can start enjoying doing the things you love again.