Dogs often itch and scratch and that's completely fine. But, there are times when scratching that's too frequent indicates certain health problems. As a responsible dog owner, you should know to tell apart the wrong kind of itching from the normal itch. Read on and discover what could be causing your dog's itchy skin and what you can do about it.
Itchy skin can be a complete nightmare for dogs and owners alike! The official medical term for itching is pruritus, and it is an extremely common complaint in dogs. Dogs can itch until their skin is red, sore and infected, and owners can often feel completely helpless watching their pet feel so uncomfortable.
Unfortunately, there is not just one single cause for itchy skin in dogs, there are many different reasons why your dog could be feeling itchy. Sometimes the cause is obvious like fleas, while at other times it may be more difficult to diagnose and you may need the help of your veterinarian.
In this article, we will discuss many of the common causes of itchiness in dogs and how they are diagnosed, so that you will be better informed about the health of your dog. We will also look at the remedies used to treat itchy skin. First, let’s take a look at the signs your dog might show if his skin is itchy.
Signs of Itchy Skin
A dog with itchy skin can show a variety of signs. He will bite, itch, rub and lick the areas of his body that are itchy. Sometimes only one or two areas are affected, or the entire body can be itchy. If the itching is severe the dog may also feel depressed, and act different than normal. Some dogs might even have a decreased appetite or reluctance to do exercise.
Common clinical signs include:
- Redness of the skin
- Hives (sign of an allergic reaction, little raised bumps on the skin)
- Spots or crusts on the skin
- Licking the paws or legs
- Biting and licking the skin
- Rubbing up against furniture or the floor
- Hair loss
Causes of Itchy Skin
As we mentioned earlier, there are a lot of causes of itchy skin in dogs. This is what makes it quite a frustrating problem. Sometimes the cause is obvious like fleas or a reaction to using a new washing powder on your dog’s bed, and at other times the cause of the itchiness can be quite difficult to diagnose.
The list of possible causes is very long, therefore, we have arranged the common causes of itching in dogs into helpful groups. Let’s take a closer look at these different causes of itching in a little more detail:
Parasites (fleas, mites, ticks)
Fleas are a very common cause of itching in dogs(1). These tiny brown little critters feed on dog’s blood and make the dog itch every time they bite.
They can be clearly seen on the dog’s skin but move and jump quite fast, so sometimes it takes experience to find them. They are most commonly encountered at the base of the tail and along the back. They cause intense itching and redness of the skin.
There are many different types of mites (2) which can also cause your dog to feel itchy. Sarcoptes and Demodex are two of the most common canine mites.
Sarcoptes mites (also known as scabies) commonly cause hair loss and intense itching around the chest, ears, and elbows. Demodex mites usually cause a mild itch, with lesions of hair loss and scaly skin, on the face, legs, and paws.
Mites can’t be seen with the naked eye, and a veterinarian will need to take a quick sample of skin or hair to look at under a microscope to diagnose the problem.
Ticks are another type of blood-sucking parasite that can cause your dog to itch and bite at its skin. They can latch on anywhere, but especially along the legs or in armpits. These pesky pests can also bite humans and transmit a number of diseases, so it is important to check your dog for them during tick season(3).
Allergies are another common cause of itching in dogs. Environmental allergens can include almost anything your dog might come into contact within the home or outside including dust, molds, dust mites, storage mites, pollens or grass.
Allergies may be seasonal, with your dog only itching in the summer due to a pollen allergy, or may occur all year round if it is an allergy to dust or molds in the home. These type of allergies can cause a condition known as atopic dermatitis(4).
The dog’s immune system over-reacts to certain particles, or allergens, it comes into contact with. The dog’s immune system recognizes the allergen as an invader into the body and triggers an attack against it causing itchiness and redness of the skin.
Allergic dermatitis commonly affects the paws, ears, armpits, and face, but can affect the whole body in severe cases. The skin is red and itchy often with little spots. As the dog continues to scratch and lick it can lead to hair loss, staining of the hair from continual licking, crusting and skin infections.
Skin that is dry and flaky will make your dog feel very itchy. Often just a slight touch along your dog’s back can make him start an itching spree. The skin may appear dry and tough with dandruff-like flakes.
If you live in an area with low humidity, then this may cause dryness of the skin. If you bathe your dog too frequently or using a harsh shampoo, you could be removing the natural oils from its skin and coat, and causing the dry skin. Finally, dry skin can also be caused by a poor diet.
Food allergies and sensitivities can cause a variety of signs from dry, itchy skin to ear infections to vomiting and diarrhea. A food allergy often causes the ears and paws of the dog to be itchy, but in severe cases can cause the entire body to be red and itchy.
Food hypersensitivity reactions can occur a few minutes after eating a new food or a few days later, and often cause an upset tummy. However, some food allergies may develop after feeding the offending food allergen to your dog for YEARS before the allergy develops.
This is why food allergies can be quite difficult to diagnose! A canine study in the United States found that the most common food allergens for dogs were beef, soy, chicken, chicken egg, cow’s milk, wheat and corn(5).
They can also cause hair loss, scaling, pus-filled spots and red sore spots on the skin. These types of infections can pop up anywhere on a dog’s body. Dog’s with long, thick hair are often more prone to these infections, as the skin often becomes hot and moist, the perfect environment for bacteria to grow! Often the affected areas will be smelly and very sore to touch.
Contact dermatitis is not a very common cause of itching in dogs(8). It is caused by direct contact of something onto the skin of the dog, which then causes inflammation of the skin (dermatitis). The clinical signs typically occur only in the area where the allergen touched the skin.
Common examples include flea collars, pesticides used on the lawn, a new dog bed, using a new dog shampoo or a new washing powder. If the dog is allergic to any of those examples, there will be redness and itching where it contacted the skin. Removing the allergen, (i.e. changing the dog bed, removing the flea collar) often solves the problem.
Diagnosing the cause of itching is a process of elimination. Firstly, parasites should be ruled out. Fleas are the most common cause of itchy skin in dogs. You should check carefully through your dog’s coat, looking for fleas, flea dirt (little brown specks of flea poop!), or ticks. A flea comb is a really helpful tool to help you do this.
Try to think about when the itch happens: Only after walks in long grass? After you bought your dog a new dog bed or used a new dog shampoo? Only in the summer? You may be able to figure out the cause and prevent it from happening again.
Often you will need the help of your veterinarian, especially if your dog has been itching for a while. A veterinarian will ask you lots of questions about your dog to develop a detailed clinical history.
They will then carry out a full clinical examination- examining your pet from head to toe. Sometimes they might suggest a swab sample to check for bacteria or yeast on the skin, or a hair pluck or skin scrape to check for mites.
There are blood tests and skin tests for allergen testing. These can be helpful when trying to diagnose allergies, however, they are not 100% accurate. The diagnosis of atopic dermatitis is complicated, it is usually diagnosed based on the breed, history and clinical signs that the dog is showing.
Extensive research has allowed veterinarians to have certain criteria to help them diagnose it(9).
A food allergy is diagnosed by doing an elimination diet. An elimination diet can be home cooked (but it is best to seek the advice of a veterinarian or animal nutritionist!) or a commercially bought hypoallergenic diet.
In simple terms, it involves feeding your dog a novel protein and a novel carbohydrate source, something which he hasn’t eaten before. Ideally, the new diet is fed exclusively for at least 8 weeks (NO treats, NO flavored toys, and NO human food) before deciding if it has worked(10).
It takes a long time for food allergen particles to work their way out of your dog’s body, so it is important not to give up half way through!
Fleas, ticks, and mites are treated with individual anti-parasitic treatments, which could be a spot-on, tablet or a treated collar for your dog. These might need to be repeated regularly throughout the year to keep your pet free from parasites.
Skin infections require a course of antibiotics or anti-fungal treatment, depending on the underlying cause. The duration of treatment might range from a week in mild infections, to a few months, in the case of a severe skin infection. Your vet might also prescribe a medicated or soothing shampoo to help your dog’s sore skin.
It is important that the dog feels less itchy as soon as possible. Often a vet will prescribe anti-histamines to help with mild allergies, and reduce the itch and redness in the skin.
Coconut oil might also be quite useful in healing your dog’s skin and reducing the itching.
The best treatment for allergies is avoiding the offending allergen. However, this is not always easy! In severe or chronic allergy cases, corticosteroids or immuno-suppressants such as cyclosporine or oclacitinib, might be necessary.
These help to stop the body reacting to the allergen, therefore quickly reduce the itch. They do carry certain risks and may have side effects if used long term, therefore it is important to discuss treatment options carefully with your veterinarian.
Changing your dog’s diet to a hypoallergenic diet or adding certain supplements might also help, especially if he suffers from allergies or chronic skin problems. Essential fatty acids (omega 3 and 6) as well as vitamins B, C and E are important for healthy skin, to support the immune system and reduce inflammation.
We know that watching your dog constantly scratch can be very frustrating. With so many possible underlying causes, it is not always easy to figure out what is causing the itch! It is better to try to stop the itch sooner rather than later, as your dog may quickly cause the skin to become red, sore and infected.
Fleas are a very common cause of itching in dogs, and you can check for these at home, using a flea comb to search your dog’s coat. In many cases, you might need help from your veterinarian, especially if you think your dog has an allergy. Hopefully, after reading this article you are better informed about all the possible causes of itching in dogs and the remedies too!
This article has been written by Dr Margarita Boyd, BVSc MRCVS.
Margarita graduated from the University of Liverpool, earning a Bachelor in Veterinary Science with distinction. She worked in small animal and equine practice for a few years, before choosing to focus solely on companion animals. She has developed a special interest in internal medicine and ophthalmology.