Scratching, pruritus and itching of the dog: causes and treatments

Pruritus is the scientific word for any form of excessive scratching, itching, biting or licking of your dog. A dog has every right to experience scratching at times. However, when this becomes recurrent, skin lesions may appear and this becomes more worrisome. Generally speaking, when your dog scratches a lot, a vicious circle sets in and maintains the itching. It is important to keep in mind that if your dog irritates you by scratching a lot, he suffers as well! There are many causes of itching in dogs that we will detail here. In most cases, a treatment can reduce the desire to scratch and therefore the associated lesions.

First cause: external parasites

External parasites are any insects or mites that come into contact with your dog’s skin and cause itching. The main insect involved is the flea. This insect is unfortunately present everywhere in the environment and pulls up very quickly. The dog scratches himself because the flea bites him to feed on blood, but the dog can also develop allergic reactions against the flea bite (against the flea’s saliva) and this will accentuate the pruritus: this is called DAPP (dermatitis by allergy to flea bites). It is important to know that when you see a flea on your pet, it may mean that the environment (the house) also contains fleas. In fact, for a flea present on your pet, there are about 90 times more eggs ready to hatch in the environment! Unfortunately, it often happens that fleas are not seen on the dog even though they are present. You should think about this when the dog has a tendency to scratch at the base of the tail, in the dorsolumbar region.

Other parasites involved include scabies, lice, aoutats, Cheyletielles,… All these parasites generally cause scratching.

Treatment :

The application of pest control products is the most effective method to get rid of these pests. The products are mostly effective for fleas and other types of pests. It is advisable to treat your dog against fleas every month because he can catch fleas on a simple walk or you can bring eggs under your shoes which will then hatch in your house.
Treatments exist in various forms: tablets, pipette, collar… It is also advisable to treat your home when there are fleas on your pet because fleas/eggs hide and can re-infest your animals.

Second cause: a skin infection

Dogs have a natural bacterial and fungal flora on their skin. This flora helps to protect the skin. However, when the dog scratches a lot, the skin is less protected because of pruritus-induced microlesions, and therefore these normally harmless bacteria and fungi can then proliferate abnormally. This causes an inflammatory reaction of the skin (dermatitis) which then accentuates the itching. The skin lesions then become extensive with patches, scabs, raw skin and sometimes even pus.
Fungal infections usually cause less itching but also lead to skin lesions.

Treatment : In most cases, antibiotic and/or anti-mycotic treatment is necessary. However, it is also necessary to cause the primary cause of scratching (often external fleas/parasites) to stop the vicious circle.

Third cause: an allergy

Allergies can be of any type and the allergen, i.e. the element causing the allergy, is unfortunately not always detected. Allergies generally manifest themselves by pruritus but other symptoms can be associated with it (diarrhea, depilation, …). We have already mentioned DAPP which is an allergy due to flea bites.

  • The food allergy: as its name suggests, this allergy has its origins in food. Indeed, the dog’s organism can “react” in an abnormal way to certain components of its food ration and this can cause pruritus. This is often an allergy or intolerance to certain types of protein (beef, chicken, milk, etc.). It is sometimes difficult to find out which constituent is the cause of the allergy. It is then necessary to set up, with the help of your veterinarian, an eviction diet: this involves completely changing your dog’s ration for several weeks and bringing him instead a ration with “new” proteins, which his body has never encountered (horse, sheep protein, …). Then, the foods suspected of causing an allergy are reinserted into the ration one by one to evaluate the impact of each one.

Treatment: if the process to identify the allergen of the food in question is sometimes complicated, when it is well identified, the treatment is very easy. Simply avoid any food containing this allergen in your dog’s ration.

  • Allergy to the environment: this allergy can be very restrictive because the allergens are permanently located in the environment and therefore very difficult to remove. It can be pollen, dust, dust mites…As with other allergies, there is usually an itch associated with it.

Treatment: This allergy is difficult to treat because of the omnipresence of allergens (also called aeroallergens). Desensitization protocols are possible but not always effective. Treatments based on antihistamines or corticoids are also sometimes necessary.

  • Special case: canine atopic dermatitis (or atopy): This is a chronic disease that appears in a relatively young dog (usually between 1 and 6 years old). This disease is due to a predisposition to develop several allergies against various allergens (food, dust, dust mites, pollen, fleas…) and also due to the skin which is more fragile and therefore less protective and therefore lets allergens pass more easily and lets infections develop more easily.

The majority of symptoms are pruritus often associated with recurrent ear infections, inflammation of the fingers (the dog licks or bites his paws very frequently).

The disease is mainly of genetic origin with certain predisposed breeds such as French Bulldogs, Labrador, Sharpei, Westie, Yorshire, Boxer…This means that if your pet is affected by this disease, he will have it for the rest of his life. However, this disease is not contagious.

Treatment: This one is really difficult and it is not a question of curing but of significantly reducing the symptoms (including pruritus). This is done by eliminating allergens (mainly food), and treating itching and related skin infections. The use of shampoo to reduce inflammation of the skin and provide protection is often recommended.

Desensitization is also possible.

A background treatment with antihistamines and/or corticosteroids is often necessary to manage crises during which the dog is desperately scratching.

For these dogs, it is important to treat any source that can cause skin lesions and pruritus and therefore the use of antiparasitic medication on a monthly basis is indispensable (especially against fleas).

In all cases, your veterinarian will be in the best position to give you treatment and advice.

Finally, it is important to keep in mind that all these causes of pruritus (non-exhaustive list) can be present at the same time or only some of them. Indeed a dog can be allergic to pollens and also to food but not to dust mites. All combinations are possible.